Composite pigment and production method thereof, paint composition containing composite pigment, and coating film

ABSTRACT

The purpose of the present invention is to provide a composite pigment which can be dispersed and made into paint in a manner that saves labor compared with conventional flat emulsion paints, and which can achieve concealing properties and low glossiness (a luster reduction effect) without separately adding a matting agent. This composite pigment contains an inorganic compound and/or an organic compound, and a fixed extender pigment.

TECHNICAL FIELD

The present invention relates to a composite pigment, a method forproducing the composite pigment, a paint composition containing thecomposite pigment, and a paint film. Specifically, the present inventionis as follows.

The present invention (the first invention of the present application)relates to a composite pigment containing an extender pigment and aninorganic compound, a method for producing the composite pigment, apaint composition containing the composite pigment, and a paint film.

The present invention (the second invention of the present application)relates to a composite pigment containing a titanium oxide pigment, amethod for producing the composite pigment, a paint compositioncontaining the composite pigment, and a paint film.

The present invention (the third invention of the present applicationand the fourth invention of the present application) relates to acomposite pigment containing an inorganic color pigment, a method forproducing the composite pigment, a paint composition containing thecomposite pigment, and a paint film.

The present invention (the fifth invention of the present application)relates to a composite pigment containing an extender pigment and aninorganic compound and/or organic compound, a method for producing thecomposite pigment, a composite pigment further containing an inorganiccolor pigment such as a titanium oxide pigment, a method for producingthe composite pigment, and a paint composition containing the compositepigments, and a paint film.

BACKGROUND ART

By applying a matting paint to a surface of a target, the colorimpression or texture of the target is modified. For example, byapplying a matting paint to an inner wall of a house, a relaxedatmosphere can be produced indoors. In addition, by applying a mattingpaint to a wall surface or a member which receives sunlight, or lightfrom lighting equipment or the like, reflection of furniture, plants,persons or the like can be reduced. Further, a matting paint may beapplied to a vehicle main body. In general, coating for vehicles isoften “glossy”, and by applying a matting paint, a distinctive andunique design can be created.

In the former applications (building materials and the like), among theapplications described above, generally a color gloss paint to which amatting agent is added (color matting paint) is used. On the other hand,in the latter applications (vehicles and the like), generally a colorgloss paint, a pearl paint or the like is applied to a vehicle main bodyto form a base layer, and a transparent matting paint is applied ontothe base layer to form a top layer.

Heretofore, silica, resin beads and the like have been used as mattingagents (e.g. Patent Literatures 1 and 2). Among them, silica mattingagents have a good matte property, and are widely used in theabove-described building material applications and vehicle applications.

Meanwhile, a silica matting agent is apt to cause an increase inviscosity of a matting paint containing the matting agent. Inparticular, when the amount of the matting agent blended is increasedfor the purpose of enhancing the degree of a gloss reduction, theviscosity of the paint markedly increases, so that the workability(handling) of the coating is deteriorated. On the other hand, forexample, Patent Literature 3 suggests that an increase in viscosity of apaint is reduced by using a mixture of hydrophobic silica and aninorganic filler (calcium carbonate, mica, talc, clay or the like) as amatting agent.

Various attempts have been made to use a mixture of silica and aninorganic filler (extender pigment) as a matting agent for variouspurposes other than reduction of an increase in viscosity of a paint.For example, Patent Literature 4 suggests that deterioration of theappearance quality of a paint film due to aggregation of silica isreduced or an increase in gloss of a matting paint film due to frictionis reduced by blending a mixture of silica and talc as a matting agentin a transparent (clear) matting paint for vehicles. Patent Literature 5suggests that an increase in gloss of a matting paint film due tofriction is reduced by blending a mixture of spherical silica gel and anextender pigment (calcium carbonate or barium sulfate) as a mattingagent in a matting overprint varnish composition.

As pigments having a high gloss, inorganic color pigments such astitanium oxide pigments are used in a wide range of applications.However, in some applications, a high gloss is not required, andpigments having a low gloss are favored. For example, when a pigmenthaving a low gloss is used for a coating material for a building or thelike, a relaxed atmosphere can be produced. In addition, when a pigmenthaving a low gloss is used for a wall surface or a member which receivessunlight or light from lighting equipment or the like, reflection offurniture, plants, persons or the like can be reduced.

For preparing a paint film having a low gloss and a low luster ingeneral, a flat emulsion paint containing a titanium oxide pigment andporous calcium carbonate is used as described in, for example, PatentLiterature 6. The calcium carbonate forms fine irregularities on thesurface of a paint film, so that diffusion of incident light can befacilitated to exhibit a matte effect. Patent Literatures 1, 2 and 7suggest that a matting agent of spherical silica, silicate particles orresin beads is added to a gloss paint (gloss emulsion paint) containinga titanium oxide pigment or the like.

A matting paint may be used as a coating material for a building or thelike. For example, by applying a matting paint to an inner wall of abuilding, a relaxed atmosphere can be produced on the inner wall. Inaddition, by applying a matting paint to a wall surface or a memberwhich receives sunlight, or light from lighting equipment or the like,reflection of furniture, plants, persons or the like can be reduced.

In general, a matting paint contains an inorganic color pigment (e.g.inorganic white pigment such as titanium dioxide), and a component forreducing gloss. For example, Patent Literature 6 discloses a flatemulsion paint containing a titanium dioxide pigment and porous calciumcarbonate. The calcium carbonate forms fine irregularities on thesurface of a paint film, so that diffusion of incident light isfacilitated to exhibit a matte effect. Patent Literatures 1 and 2suggest that a matting agent of spherical silica, resin beads or thelike is added to a gloss paint (gloss emulsion paint) containing atitanium dioxide pigment or the like.

In addition, an attempt has been made to obtain a matting paint and amatting paint film without using a component for reducing gloss. Forexample, Patent Literature 8 suggests that on the surface of rutile-typeor anatase-type titanium dioxide having an average particle diameter of0.15 to 0.3 hydrous silicon and hydrous aluminum are provided as SiO₂and Al₂O₃ in an amount of 2 to 15% by weight and an amount of 1 to 10%by weight, respectively, and an organic metal compound such as anorganic silicon compound is provided in an amount of 0.05 to 5% byweight. It is stated that such a titanium dioxide pigment makes itpossible to obtain a paint exhibiting high hiding power and an excellentmatte effect without using a component for reducing gloss, and isexcellent in storage stability.

By applying a matting paint to a surface of a target, the colorimpression or texture of the target is modified. For example, byapplying a matting paint to an inner wall of a house, a relaxedatmosphere can be produced indoors. In addition, by applying a mattingpaint to a wall surface or a member which receives sunlight, or lightfrom lighting equipment or the like, reflection of furniture, plants,persons or the like can be reduced.

As a matting paint, for example, a flat emulsion paint is known whichcontains an inorganic color pigment (titanium dioxide pigment) andporous calcium carbonate as described in Patent Literature 6. Thecalcium carbonate forms fine irregularities on the surface of a paintfilm, so that diffusion of incident light is facilitated to exhibit amatte effect. Patent Literatures 1 and 2 discloses a matting paintobtained by adding a matting agent of spherical silica, resin beads orthe like to a gloss paint containing an inorganic color pigment(titanium dioxide pigment or the like).

CITATION LIST Patent Literatures

Patent Literature 1: JP 08-209029 A

Patent Literature 2: JP 2005-187701 A

Patent Literature 3: JP 09-157545 A

Patent Literature 4: JP 2013-28778 A

Patent Literature 5: JP 2005-272586 A

Patent Literature 6: JP 2012-92289 A

Patent Literature 7: JP 2016-3250 A

Patent Literature 8: JP 09-25429 A

SUMMARY OF INVENTION Technical Problem

As described above, the matting agents (mixed systems of silica and anextender pigment) described in Patent Literatures 3 to 5 have anadvantage that an increase in viscosity of a paint is reduced to exhibitexcellent handling over a matting agent of silica alone, and the like.Meanwhile, these matting agents are inferior in matte effect to amatting agent of silica. In addition, when an extender pigment is usedin combination, the tactile feeling of a matting paint film tends to bedeteriorated (the paint film has a rough tactile feeling).

In the case of the above-described flat emulsion paint, it is necessaryto strongly disperse pigment components for ensuring that calciumcarbonate in a paint exhibits a matte effect, and an inorganic colorpigment (e.g. titanium oxide pigment) sufficiently exhibits pigmentproperties such as a hiding power. This leads to an increase in laborfor formation of the paint.

In addition, a combination of a matting agent and a gloss paint (glossemulsion paint) has the problem that field operation is complicatedbecause when a matting agent is added to a paint at a construction site,an operator is required to weigh the matting agent, and stir and mix thematting agent and the paint. Further, addition of the complicatedoperation may cause construction failure. In addition, the matting agentis generally expensive, leading to an increase in cost of the paint.

In the case of the above-described flat emulsion paint described inPatent Literature 6, a high matte effect is easily obtained, but sincelarge irregularities are formed on the surface of a paint film, thetactile feeling of the paint film is deteriorated (the paint film has arough tactile feeling). In addition, in the case of a combination of agloss emulsion paint and a matting agent, a moderate matte effect and amoderate tactile feeling (smoothness) of the paint film are obtained,but either of the matte effect and the tactile feeling is notsufficient, and the matting agent is expensive, leading to an increasein cost. Further, in the case of the titanium dioxide pigment describedin Patent Literature 3, reduction of gloss is not sufficient, andtherefore a sufficient matte effect is not obtained.

Thus, the above-described conventional techniques have the problem thatit is difficult to secure both the matte effect and the tactile feelingof the paint film such that enhancement of the matte effect leads todeterioration of the tactile feeling of the paint film, andprioritization of the tactile feeling of the paint film leads toreduction of the matte effect.

The above-described problem arises not only when an inorganic whitepigment such as titanium dioxide is used, but also when anotherinorganic color pigment is used.

In the case of the conventional flat emulsion paint, a high matte effectand a sufficient hiding power are obtained, but it is accordinglynecessary to strongly disperse pigment components. This leads to anincrease in labor for formation of the paint.

In addition, in the case of a combination of a gloss paint and a mattingagent, a moderate matte effect is obtained, but the matte effect is notsufficient. Of course, when the amount of the matting agent blended isincreased, the matte effect is enhanced, but the viscosity of the paintis increased. This also leads to an increase in production cost of thepaint because the matting agent which is expensive is blended in a largeamount.

The present invention has been made in view of the situations describedabove, and an object of the present invention is to provide a compositepigment which can be dispersed and formed into a paint in a labor savingmanner, and is capable of exhibiting a sufficient low-gloss property(matte effect) and hiding power without using a matting agent, a methodfor producing the composite pigment, a paint composition containing thecomposite pigment, and a paint film containing the composite pigment.

Solution to Problem

The present inventors have extensively conducted studies for solving theabove-described problems, and resultantly found, for the first time,that when as a matting agent, a composite pigment is used in which anextender pigment such as barium sulfate is fixed with an inorganiccompound such as silica, a matting paint composition having a lowviscosity and excellent handling can be obtained, and a high matteeffect in a state of a paint film, and a good tactile feeling of thepaint film can be attained.

The present inventors have extensively conducted studies for solving theabove-described problems, and resultantly found, for the first time,that when a composite pigment is used in which a titanium oxide pigmentand an extender pigment are fixed, the composite pigment can bedispersed and formed into a paint in a labor saving manner as comparedto a conventional flat emulsion paint, and a low-gloss property (matteeffect) and a hiding power can be attained without adding a mattingagent separately.

In addition, the present inventors have extensively conducted studiesfor solving the above-described problems, and resultantly found, for thefirst time, that when a composite pigment is used in which an inorganiccolor pigment such as titanium dioxide is fixed with an inorganiccompound, the composite pigment having a specific particle sizedistribution, it is possible to achieve both a low gloss (a low luster)and a good tactile feeling of the paint film in a paint (paint film)containing the composite pigment.

In addition, the present inventors have extensively conducted studiesfor solving the above-described problems, and resultantly found, for thefirst time, that when an inorganic color pigment such as a titaniumdioxide pigment, which contains a zinc element is fixed with aninorganic compound, the particle size of a composite pigment can beappropriately increased, so that it is possible to exhibit a high matteeffect in a paint film formed using a paint containing the compositepigment.

In addition, the present inventors have extensively conducted studiesfor solving the above-described problems, and resultantly found, for thefirst time, that when a composite pigment is used in which an inorganiccolor pigment such as a titanium oxide pigment and an extender pigmentare fixed with an inorganic compound and/or organic compound, thecomposite pigment can be dispersed and formed into a paint in a laborsaving manner as compared to a conventional flat emulsion paint, and alow-gloss property (matte effect) and a hiding power can be attainedwithout adding a matting agent separately.

On the basis of these findings, the present inventors have completed thepresent invention (“the first invention of the present application” to“the fifth invention of the present application”) as described below.

Specifically, the first invention of the present application includes:

(1-1) a composite pigment in which an extender pigment is fixed with aninorganic compound;

(1-2) the composite pigment according to (1-1), wherein a diameter oncumulative 50% (D50) in a volume cumulative distribution measured by alaser diffraction/scattering-type particle size distribution measuringapparatus is 1 to 15 μm;

(1-3) the composite pigment according to (1-1) or (1-2), wherein adiameter on cumulative 90% (D90) in the volume cumulative distributionmeasured by the laser diffraction/scattering-type particle sizedistribution measuring apparatus is 5 to 30 μm;

(1-4) the composite pigment according to any one of (1-1) to (1-3),wherein an oil absorption measured by a method specified in JIS K5101-13-1 is 80 (ml/100 g) or less;

(1-5) the composite pigment according to any one of (1-1) to (1-4),wherein the extender pigment is barium sulfate;

(1-6) the composite pigment according to any one of (1-1) to (1-5),wherein the inorganic compound is an inorganic silicon compound;

(1-7) a matting agent comprising the composite pigment set forth in anyone of (1-1) to (1-6);

(1-8) a paint composition comprising at least the composite pigment ormatting agent set forth in any one of (1-1) to (1-7), and a resin;

(1-9) the paint composition according to (1-8), comprising a dispersanthaving an amine value;

(1-10) the paint composition according to (1-8) or (1-9), comprising acolor material;

(1-11) The paint composition according to any one of (1-8) to (1-10),wherein the paint composition is a paint composition for formation of amatting top coat, which is applied onto a color base layer;

(1-12) a paint film formed using the paint composition set forth in anyone of (1-8) to (1-11);

(1-13) a method for producing a composite pigment, comprising adjustinga pH of a slurry containing an inorganic compound source and an extenderpigment, so that an inorganic compound derived from the inorganiccompound source is precipitated to fix the extender pigment; and

(1-14) the method for producing a composite pigment according to (1-13),comprising preparing the slurry in such a manner that a volume ratio(Va/Vb) of a volume (Va) of the inorganic compound source, which iscalculated in terms of an inorganic compound, to a volume (Vb) of theextender pigment is 0.1 to 3.

The second invention of the present application includes:

(2-1) a composite pigment in which at least a titanium oxide pigment andan extender pigment are fixed with an inorganic compound and/or organiccompound;

(2-2) the composite pigment according to (2-1), wherein at least aplurality of titanium oxide pigments and a plurality of extenderpigments are fixed with an inorganic compound and/or organic compound;

(2-3) the composite pigment according to (2-1) or (2-2), wherein adiameter on cumulative 90% (D90) in a volume cumulative distributionmeasured by a laser diffraction/scattering-type particle sizedistribution measuring apparatus is 20 μm or less;

(2-4) the composite pigment according to any one of (2-1) to (2-3),wherein a diameter on cumulative 50% (D50) in the volume cumulativedistribution measured by the laser diffraction/scattering-type particlesize distribution measuring apparatus is 1 to 10 μm;

(2-5) the composite pigment according to any one of (2-1) to (2-4),wherein the extender pigment is calcium carbonate and/or barium sulfate;

(2-6) the composite pigment according to any one of (2-1) to (2-5),wherein the inorganic compound is an inorganic silicon compound;

(2-7) the composite pigment according to any one of (2-1) to (2-6),further comprising an inorganic compound and/or organic compound forsurface treatment on a surface of the composite pigment;

(2-8) a matting pigment comprising the composite pigment set forth inany one of (2-1) to (2-7);

(2-9) a building wall surface coating pigment comprising the compositepigment set forth in any one of (2-1) to (2-7);

(2-10) a building material coating pigment comprising the compositepigment set forth in any one of (2-1) to (2-7);

(2-11) an automobile coating pigment comprising the composite pigmentset forth in any one of (2-1) to (2-7);

(2-12) a furniture coating pigment comprising the composite pigment setforth in any one of (2-1) to (2-7);

(2-13) an electric and mechanical product coating pigment comprising thecomposite pigment set forth in any one of (2-1) to (2-7);

(2-14) a method for producing a composite pigment in which a diameter oncumulative 50% (D50) and a diameter on cumulative 90% (D90) in a volumecumulative distribution measured by a laser diffraction/scattering-typeparticle size distribution measuring apparatus is 1 to 10 μm and 20 μmor less, respectively, the method comprising preparing a slurrycontaining at least a titanium oxide pigment, an extender pigment, andan inorganic compound and/or organic compound, and fixing, understirring, at least the titanium oxide pigment and the extender pigmentwith the inorganic compound and/or organic;

(2-15) a paint composition comprising the pigment set forth in any oneof (2-1) to (2-13); and

(2-16) a paint film formed using the paint composition set forth in(2-15).

The third invention of the present application includes:

(3-1) a composite pigment in which an inorganic color pigment is fixedwith an inorganic compound, wherein

an abundance ratio of the composite pigment having a particle diameterof 1 μm or more in a volume cumulative distribution measured by a laserdiffraction/scattering-type particle size distribution measuringapparatus is 50% or more based on the total amount of the compositepigment, and a diameter on cumulative 90% (D90) is 30 μm or less;

(3-2) the composite pigment according to (3-1), wherein the abundanceratio of the composite pigment having a particle diameter of 2 μm ormore in the volume cumulative distribution is 30% or more based on thetotal amount of the composite pigment;

(3-3) the composite pigment according to (3-1) or (3-2), wherein whenfor a paint composition containing the composite pigment and an acrylicresin, a specular gloss is measured by a method specified inJIS-K5600-4-7, the specular gloss is 5% or less under a geometriccondition of 60°;

(3-4) the composite pigment according to any one of (3-1) to (3-3),wherein when for a paint composition containing the composite pigmentand an acrylic resin, a specular gloss is measured by the methodspecified in JIS-K5600-4-7, the specular gloss is 40% or less under ageometric condition of 85°;

(3-5) the composite pigment according to any one of (3-1) to (3-4),wherein the inorganic color pigment is at least one selected from thegroup consisting of titanium dioxide, lower titanium oxide, titaniumoxynitride, zinc oxide, basic lead carbonate, carbon black, bone black,graphite, iron black, cobalt chromate black spinel, iron chromatecomposite oxide, copper chromate spinel black composite oxide, Fe—Mn—Biblack, red iron oxide, molybdenum red, nickel antimony titanium yellow,chrome antimony titanium buff, synthetic iron oxide yellow, chromeyellow, ultramarine blue, iron blue, cobalt blue, cobalt green, chromegreen, chromium oxide green, cobalt chromate green spinel and cobalttitanate green spinel;

(3-6) the composite pigment according to any one of (3-1) to (3-5),wherein the inorganic compound is an inorganic silicon compound;

(3-7) a matting pigment comprising the composite pigment set forth inany one of (3-1) to (3-6);

(3-8) a paint composition comprising the composite pigment set forth inany one of (3-1) to (3-7), and a resin;

(3-9) a paint film formed using the paint composition set forth in(3-8);

(3-10) a paint film according to (3-9), wherein the paint film containsthe composite pigment and an acrylic resin, and when a specular gloss ismeasured by a method specified in JIS-K5600-4-7, the specular gloss is5% or less under a geometric condition of 60°;

(3-11) the paint film according to (3-9) or (3-10), wherein the paintfilm contains the composite pigment and an acrylic resin, and when aspecular gloss is measured by a method specified in JIS-K5600-4-7, thespecular gloss is 40% or less under a geometric condition of 85°; and

(3-12) a method for producing a composite pigment, comprising:

preparing a slurry having a solid concentration of 75 to 450 g/L andcontaining an inorganic compound source and an inorganic color pigmentin such a manner that a volume ratio (Va/Vb) of a volume (Va) of theinorganic compound source, which is calculated in terms of aprecipitated inorganic compound, to a volume (Vb) of the inorganic colorpigment is 0.3 to 2; and

adjusting a pH of the slurry so that an inorganic compound derived fromthe inorganic compound source is precipitated to fix the inorganic colorpigment.

The fourth invention of the present application includes:

(4-1) a composite pigment in which an inorganic color pigment containinga zinc element is fixed with an inorganic compound;

(4-2) the composite pigment according to (4-1), wherein the inorganiccolor pigment and an extender pigment are fixed with the inorganiccompound;

(4-3) the composite pigment according to (4-1) or (4-2), wherein thezinc element is present on at least a surface of the inorganic colorpigment;

(4-4) the composite pigment according to any one of (4-1) to (4-3),wherein the zinc element is present as zinc oxide and/or zinc hydroxide;

(4-5) the composite pigment according to any one of (4-1) to (4-4),wherein an abundance ratio of the composite pigment having a particlediameter of 2 μm or more in a volume cumulative distribution measured bya laser diffraction/scattering-type particle size distribution measuringapparatus is 70% or more based on the total amount of the compositepigment;

(4-6) the composite pigment according to any one of (4-1) to (4-5),wherein a diameter on cumulative 90% (D90) in the volume cumulativedistribution measured by the laser diffraction/scattering-type particlesize distribution measuring apparatus is 30 μm or less;

(4-7) the composite pigment according to any one of (4-1) to (4-6),wherein the inorganic color pigment is a titanium dioxide pigment;

(4-8) a matting pigment comprising the composite pigment set forth inany one of (4-1) to (4-7);

(4-9) a paint composition comprising at least the composite pigmentand/or the matting pigment set forth in any one of (4-1) to (4-8), and aresin;

(4-10) the paint composition according to (4-9), comprising a dispersanthaving an amine value;

(4-11) a paint film formed using the paint composition set forth in(4-9) or (4-10); and

(4-12) a method for producing a composite pigment, comprising adjustinga slurry containing an inorganic color pigment containing a zincelement, and an inorganic compound source, and adjusting a pH of theslurry so that an inorganic compound derived from the inorganic compoundsource is precipitated to fix the inorganic color pigment.

The fifth invention of the present application includes:

(5-1) a composite pigment comprising extender pigment particles fixed toan inorganic compound and/or organic compound;

(5-2) a composite pigment in which some of the extender pigmentparticles set forth in (5-1) are replaced with an inorganic colorpigment;

(5-3) a composite pigment in which the numbers of the extender pigmentparticles and the inorganic color pigment particles set forth in (5-2)are each 2 or more;

(5-4) the composite pigment according to (5-2) or (5-3), wherein adiameter on cumulative 90% (D90) in a volume cumulative distributionmeasured by a laser diffraction/scattering-type particle sizedistribution measuring apparatus is 30 μm or less;

(5-5) the composite pigment according to any one of (5-2) to (5-4),wherein a diameter on cumulative 50% (D50) in the volume cumulativedistribution measured by the laser diffraction/scattering-type particlesize distribution measuring apparatus is 1 μm or more and 10 μm or less;

(5-6) the composite pigment according to any one of (5-1) to (5-5),wherein the extender pigment is calcium carbonate and/or barium sulfate;

(5-7) the composite pigment according to any one of (5-1) to (5-6),wherein the inorganic compound is an inorganic silicon compound;

(5-8) the composite pigment according to any one of (5-2) to (5-7),wherein the inorganic color pigment particles contain a zinc element;

(5-9) the composite pigment according to any one of (5-2) to (5-8),wherein an abundance ratio of the composite pigment having a particlediameter of 2 μm or more in the volume cumulative distribution measuredby the laser diffraction/scattering-type particle size distributionmeasuring apparatus is 70% or more based on the total amount of thecomposite pigment;

(5-10) the composite pigment according to any one of (5-2) to (5-9),wherein the inorganic color pigment is a titanium dioxide pigment;

(5-11) the composite pigment according to any one of (5-2) to (5-10),further comprising an inorganic compound and/or organic compound forsurface treatment on a surface of the composite pigment;

(5-12) a matting pigment comprising the composite pigment set forth inany one of (5-1) to (5-11);

(5-13) a method for producing a composite pigment, comprising adjustinga pH of a slurry containing an inorganic compound source and extenderpigment particles so that an inorganic compound derived from theinorganic compound source is precipitated to fix the extender pigmentparticles;

(5-14) a method for producing a composite pigment, comprising preparinga slurry containing inorganic color pigment particles, extender pigmentparticles, and an inorganic compound source and/or organic compound, andfixing, under stirring, the inorganic color pigment particles and theextender pigment particles with the inorganic compound and/or organiccompound;

(5-15) a method for producing a composite pigment, comprising preparinga slurry containing inorganic color pigment particles containing a zincelement, extender pigment particles, and an inorganic compound source,and adjusting a pH of the slurry, so that an inorganic compound derivedfrom the inorganic compound source is precipitated to fix the inorganiccolor pigment particles and the extender pigment particles;

(5-16) a paint composition comprising the composite pigment set forth inany one of (5-1) to (5-11) and/or the matting pigment set forth in(5-12), and a resin;

(5-17) the paint composition according to (5-16), comprising adispersant having an amine value; and

(5-18) a paint film comprising the paint composition set forth in (5-16)or (5-17).

Advantageous Effects of Invention

When the composite pigment of the first invention of the presentapplication is blended in a paint (paint film), gloss of the paint filmcan be sufficiently reduced. The composite pigment has the same level inthe degree of a gloss reduction as a conventional silica matting agenthaving a high matte effect.

In addition, while the composite pigment of the first invention of thepresent application is capable of exhibiting the high matte effect asdescribed above, an increase in viscosity of a paint containing thecomposite pigment can be sufficiently reduced, so that a paintcomposition having good handling can be obtained.

In addition, the composite pigment of the first invention of the presentapplication enables the paint film to have a smooth tactile feelingalthough the composite pigment contains an extender pigment whichnegatively affects the tactile feeling of the paint film.

As mentioned above, the composite pigment of the present invention isexcellent in that it is possible to attain all of a high matte effect,good handling and a good tactile feeling of the paint film, which aredifficult to attain with a conventional matting agent.

Further, the composite pigment of the first invention of the presentapplication can be dispersed and formed into a paint in a labor savingmanner only by adding the composite pigment to a resin or the like, andlightly mixing the resulting mixture. Because the composite pigment iseasily dispersed, uneven loss of gloss (variation in the degree of agloss at different positions on the paint film) can be reduced. Inaddition, the composite pigment of the present invention is composed ofrelatively inexpensive materials, and therefore a composite pigment, anda paint composition containing the composite pigment can be produced atlow cost. Furthermore, by appropriately selecting the types of anextender pigment and an inorganic compound that form the compositepigment, a matting agent having an environmental load lower than that ofa resin bead-based matting agent can be obtained.

When a titanium oxide pigment is used, the composite pigment of thesecond invention of the present application has sufficient titaniumoxide pigment properties (whiteness, hiding power, color property andthe like), and an effect of reducing a gloss and a luster which a whitepigment of the titanium oxide has.

Specifically, a gloss can be reduced even to the degree of a glossreduction referred to as “matting (specular gloss of 5% or less at 60°)”over the degree of a gloss reduction generally referred to as “70% gloss(specular gloss of 55 to 65% at 60° as measured in accordance with JISK5600-4-7: 1999)”, “50% gloss” or “30% gloss”.

The values of the diameter on cumulative 90% (D90) and the mediandiameter D50 of the composite pigment of the second invention of thepresent application can be each set within an appropriate range.Specifically, the diameter on cumulative 90% (D90) is set 20 μm or less,and preferably, further the median diameter D50 is set to 1 to 10 μm. Inthis way, the tactile feeling of the paint film can be made smooth whilea low-gloss property (matte effect) and a hiding power are exhibited. Atthe same time, a functionality can be imparted such that stain is hardlyattached to the pant film, or the stain is easily removed.

The composite pigment of the second invention of the present applicationcan be dispersed and formed into a paint in a labor saving manner onlyby adding the composite pigment to a paint resin or the like, andlightly mixing the resulting mixture. Therefore, a paint having alow-gloss property (matte effect) can be prepared without adding amatting agent separately, so that efficiency in field operation can beimproved, and hence occurrence of construction failure, or the like canbe reduced. Further, the composite pigment of the present invention iscomposed of relatively inexpensive materials, and therefore a paintcomposition can be produced at low cost.

The composite pigment of the third invention of the present applicationis a modified inorganic color pigment, and when the composite pigment isblended in a paint (paint film), the paint film exhibits a low gloss (alow luster). Specifically, a gloss can be reduced even to the degree ofa gloss reduction referred to as “matting (specular gloss of 5% or lessunder a geometric condition of 60° as measured in accordance with JISK5600-4-7: 1999)” over the degree of a gloss reduction generallyreferred to as “70% gloss”, “50% gloss” or “30% gloss”. In addition, thespecular gloss at 85° can be set to 40% or less, and so-called 85° glosscan be sufficiently reduced.

The composite pigment of the third invention of the present applicationenables the paint film to have a good (smooth) tactile feeling.

In the conventional technique described above, it is difficult to secureboth the matte effect and the tactile feeling of the paint film suchthat enhancement of the matte effect leads to deterioration of thetactile feeling of the paint film, and prioritization of the tactilefeeling of the paint film leads to reduction of the matte effect. Thecomposite pigment of the present invention is excellent in that it ispossible to achieve both a high matte effect and a good tactile feelingof the paint film.

Further, the composite pigment of the third invention of the presentapplication can eliminate the necessity of using a component forreducing gloss (extender pigment, matting agent or the like), so that apaint, particularly a matting paint, can be produced in a simpleprocess. The composite pigment of the present invention can be dispersedand formed into a paint in a labor saving manner only by adding thecomposite pigment to a resin or the like, and lightly mixing theresulting mixture. In addition, the composite pigment of the presentinvention is composed of relatively inexpensive materials, and thereforea paint composition can be produced at low cost.

The fourth invention of the present application provides a compositepigment in which an inorganic color pigment containing a zinc element isfixed with an inorganic compound, the particle size distribution of thecomposite pigment can be set within an appropriate range, and when thecomposite pigment is blended in a paint (paint film), the paint filmexhibits a low gloss (a low luster).

Preferably, the abundance ratio of the composite pigment having aparticle diameter of 2 μm or more in a volume cumulative distributionmeasured by a laser diffraction/scattering-type particle sizedistribution measuring apparatus can be set to 70% or more based on thetotal amount of the composite pigment. In this way, the specular glossof the paint film at 60° and the specular gloss of the paint film at 85°can be further reduced. Further, the diameter on cumulative 90% (D90)can be set to 30 μm or less, so that the tactile feeling of the paintfilm can be made smooth.

The composite pigment of the fourth invention of the present applicationcan be formed into a paint only by adding the composite pigment to aresin, and lightly mixing the resulting mixture. Therefore, it is notnecessary to strongly disperse pigment components as in the case of aconventional flat emulsion paint, and thus a matting paint can beproduced in a labor saving manner. Further, when the composite pigmentof the present invention is used, the necessity of separately adding acomponent for reducing gloss (extender pigment, matting agent or thelike) can be eliminated, so that a matting paint can be convenientlyproduced. In addition, the composite pigment of the present invention iscomposed of relatively inexpensive materials, and therefore a mattingpaint can be produced at low cost.

The composite pigment of the fifth invention of the present applicationcontains an extender pigment fixed with an inorganic compound and/ororganic compound, and therefore by blending the composite pigment in apaint (paint film), a gloss of the paint film can be sufficientlyreduced. The composite pigment has the same level in the degree of agloss reduction as a conventional silica matting agent having a highmatte effect.

In addition, while the composite pigment of the fifth invention of thepresent application is capable of exhibiting the high matte effect asdescribed above, an increase in viscosity of a paint containing thecomposite pigment can be sufficiently reduced, so that a paintcomposition having good handling can be obtained.

In addition, the composite pigment of the fifth invention of the presentapplication enables the paint film to have a smooth tactile feelingalthough the composite pigment contains an extender pigment whichnegatively affects the tactile feeling of the paint film.

As mentioned above, the composite pigment of the fifth invention of thepresent application is excellent in that it is possible to attain all ofa high matte effect, good handling and a good tactile feeling of thepaint film, which are difficult to attain with a conventional mattingagent.

When the composite pigment of the fifth invention of the presentapplication, which contains an inorganic color pigment, is blended in apaint (paint film), the paint film exhibits a low gloss (a low luster).In addition, as described above, the composite pigment of the presentinvention, in which titanium oxide is used as an inorganic colorpigment, has sufficient titanium oxide pigment properties (whiteness,hiding power, color property and the like), and an effect of reducing agloss and a luster which a white pigment of the titanium oxide has.

According to the composite pigment of the fifth invention of the presentapplication, which contains an inorganic color pigment, a gloss can bereduced even to the degree of a gloss reduction referred to as “matting(specular gloss of 5% or less at 60°)” over the degree of a glossreduction generally referred to as “70% gloss” (specular gloss of 55 to65% at 60° as measured in accordance with JIS K5600-4-7: 1999), “50%gloss” or “30% gloss”.

The values of the diameter on cumulative 90% (D90) and the mediandiameter D50 of the composite pigment of the fifth invention of thepresent application, which contains an inorganic color pigment, can beeach set within an appropriate range. Specifically, the diameter oncumulative 90% (D90) is set 30 μm or less, and preferably, further themedian diameter D50 is set to 1 to 10 μm. In this way, the tactilefeeling of the paint film can be made smooth while a low-gloss property(matte effect) and a hiding power are exhibited. At the same time, afunctionality can be imparted such that stain is hardly attached to thepaint film and the stain is easily removed.

The abundance ratio of the composite pigment having a particle diameterof 2 μm or more in a volume cumulative distribution measured by a laserdiffraction/scattering-type particle size distribution measuringapparatus can be set to 70% or more based on the total amount of thecomposite pigment. In this way, the specular gloss of the paint film at60° and the specular gloss of the paint film at 85° can be furtherreduced.

The composite pigment of the fifth invention of the present application,which contains an inorganic color pigment, can be dispersed and formedinto a paint in a labor saving manner only by adding the compositepigment to a paint resin or the like, and lightly mixing the resultingmixture. Further, a paint having a low-gloss property (matte effect) canbe conveniently prepared without adding a matting agent separately, sothat efficiency in field operation can be improved, and hence occurrenceof construction failure, or the like can be reduced. In addition, thecomposite pigment of the present invention is composed of relativelyinexpensive materials, and therefore a paint composition can be producedat low cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an electron microscope photograph of a composite pigment inExample 1-1 of the present invention.

FIG. 2 is an electron microscope photograph of a composite pigment inExample 1-2 of the present invention.

FIG. 3 is an electron microscope photograph of a composite pigment inExample 1-3 of the present invention.

FIG. 4 is an electron microscope photograph of a composite pigment inExample 1-4 of the present invention.

FIG. 5 is a volume cumulative particle size distribution diagram of thecomposite pigment in Example 1-1 of the present invention.

FIG. 6 is an electron microscope photograph of a composite pigment inExample 2-1 of the second invention of the present application.

FIG. 7 is an electron microscope photograph (enlarged view) of thecomposite pigment in Example 2-1 of the second invention of the presentapplication.

FIG. 8 is an electron microscope photograph of a composite pigment inExample 2-2 of the second invention of the present application.

FIG. 9 is an electron microscope photograph of a composite pigment inExample 2-3 of the second invention of the present application.

FIG. 10 is an electron microscope photograph of a composite pigment inExample 2-4 of the second invention of the present application.

FIG. 11 is an electron microscope photograph of a composite pigment inExample 2-5 of the second invention of the present application.

FIG. 12 is an electron microscope photograph of a composite pigment inExample 2-6 of the second invention of the present application.

FIG. 13 is an electron microscope photograph of a composite pigment inExample 2-7 of the second invention of the present application.

FIG. 14 is an electron microscope photograph of mixed powder of titaniumdioxide and calcium carbonate in Comparative Example 2-1 of the secondinvention of the present application.

FIG. 15 is an electron microscope photograph of a composite pigment inExample 3-1 of the third invention of the present application.

FIG. 16 is an electron microscope photograph of a composite pigment inExample 3-2 of the third invention of the present application.

FIG. 17 is an electron microscope photograph of a composite pigment inExample 3-3 of the third invention of the present application.

FIG. 18 is an electron microscope photograph of a composite pigment inExample 3-4 of the third invention of the present application.

FIG. 19 is an electron microscope photograph of a composite pigment inExample 3-5 of the third invention of the present application.

FIG. 20 is an electron microscope photograph of a composite pigment inExample 3-6 of the third invention of the present application.

FIG. 21 is an electron microscope photograph of a composite pigment inExample 3-7 of the third invention of the present application.

FIG. 22 is an electron microscope photograph of a composite pigment inExample 3-8 of the third invention of the present application.

FIG. 23 is an electron microscope photograph of a composite pigment inExample 3-9 of the third invention of the present application.

FIG. 24 is an electron microscope photograph of a pigment in ComparativeExample 3-1 of the third invention of the present application.

FIG. 25 is an electron microscope photograph of a pigment in ComparativeExample 3-2 of the third invention of the present application.

FIG. 26 is a volume cumulative particle size distribution diagram of thecomposite pigment in Example 3-1 of the third invention of the presentapplication.

FIG. 27 is an electron microscope photograph of a composite pigment inExample 4-1 of the fourth invention of the present application.

FIG. 28 is an electron microscope photograph (enlarged view) of thecomposite pigment in Example 4-1 of the fourth invention of the presentapplication.

FIG. 29 is an electron microscope photograph of a composite pigment inExample 4-2 of the fourth invention of the present application.

FIG. 30 is an electron microscope photograph of a composite pigment inExample 4-3 of the fourth invention of the present application.

FIG. 31 is a volume particle size distribution diagram of the compositepigment in Example 4-1 of the fourth invention of the presentapplication.

FIG. 32 is an electron microscope photograph (high-magnificationenlarged view) of the composite pigment in Example 2-1 of the secondinvention of the present application.

FIG. 33 is an electron microscope photograph (high-magnificationenlarged view) of the composite pigment in Example 4-3 of the fourthinvention of the present application.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention (“the first invention of thepresent application” to “the fifth invention of the presentapplication”) will be described in detail below.

Embodiment of the Present Invention (the First Invention of the PresentApplication)

A composite pigment of the present invention is a pigment in which anextender pigment is fixed with an inorganic compound, specifically apigment in which a plurality of extender pigment particles areaggregated in a granular shape with an inorganic compound interposedbetween the particles.

In the present invention, the “extender pigment” generally refers to apigment which is added as an extender in a vehicle, and used forimprovement of flowability, strength and optical properties, has a lowrefractive index, hiding power, and tinting strength in itself, andturns transparent or translucent when kneaded with a vehicle. Examplesof the extender pigment include barium sulfate, calcium carbonate,aluminum hydroxide, barium carbonate, kaolin and talc. In particular,use of barium sulfate as an extender pigment makes it possible to impartacid resistance, alkali resistance, heat resistance, a radiationshielding property and the like to the composite pigment.

The size of the extender pigment forming the composite pigment of thepresent invention is preferably 0.1 to 1.0 μm, more preferably 0.15 to0.7 μm, still more preferably 0.2 to 0.5 μm in terms of an averageprimary particle diameter. When the average primary particle diameter ofthe extender pigment is within the above-described range, the compositepigment has an appropriate size (preferred particle size distribution)at the time of fixing the extender pigment with an inorganic compound toaggregate the extender pigment.

The average primary particle diameter can be measured by electronmicroscopy. Specifically, extender pigment particles are photographedusing a transmission electron microscope (H-7000 manufactured byHitachi, Ltd.), image processing is performed using an automatic imageprocessing analyzer (LUZEX AP manufactured by NIRECO CORPORATION),primary particle diameters of 2000 particles are measured, and anaverage thereof is defined as an average primary particle diameter.

The shape of the extender pigment may be any shape, and the extenderpigment may have various shapes such as a spherical shape, asubstantially spherical shape, a columnar shape, needle shape, a spindleshape, an elliptical shape, a cube, a rectangular solid and anindefinite shape.

Examples of the inorganic compound to be used for fixing the extenderpigment include inorganic compounds having a fixing property oraggregating property, e.g. oxides, hydroxides and hydrous oxides ofsilicon, aluminum, zirconium, antimony, tin, cerium, zinc, titanium andthe like. More specific examples thereof include silica, aluminum oxide,aluminum hydroxide, zirconium oxide, antimony oxide, tin oxide, ceriumoxide, zinc oxide and titanium oxide, and at least one selected frominorganic compounds other than the extender pigment can be used.

The inorganic compound is preferably an inorganic silicon compound,especially preferably silica. By using an inorganic silicon compound,the specific surface area or oil absorption of the composite pigment canbe set to an appropriate value, and the handling of a paint blending thecomposite pigment can be facilitated.

In the composite pigment of the present invention, the content ratio ofthe extender pigment and the inorganic compound in the composite pigmentis preferably such that the content of the inorganic compound is 0.1 to3 parts by volume based on 1 part by volume of the extender pigment. Inaddition, the content of the inorganic compound is more preferably 0.3to 3 parts by volume based on 1 part by volume of the extender pigmentfrom the viewpoint of reduction of a gloss of a paint film. Further, thecontent of the inorganic compound is more preferably 0.1 to 1.5 parts byvolume based on 1 part by volume of the extender pigment from theviewpoint of the viscosity (handling) of a paint. In addition, thecontent of the inorganic compound is still more preferably 0.3 to 1.5parts by volume based on 1 part by volume of the extender pigment fromthe viewpoint of both reduction of a gloss of a paint film and handlingof a paint.

For fixation of the extender pigment, an organic compound having thesame property (extender pigment fixing property) as that of theinorganic compound may be used. As the organic compound, an organicflocculant, an organic coagulant or the like can be used. The organicflocculant or organic coagulant is not particularly limited as long asit is capable of catching a plurality of particles by a polymer chainthereof to aggregate the particles, and a polymer compound such as acationic polymer, an anionic polymer or a nonionic polymer can be used.The content of the organic compound can be appropriately set.

The composite pigment of the present invention is in the form of anaggregate in which an extender pigment is fixed with an inorganiccompound. Here, there may be little gaps between extender pigments(densely composite state), or gaps may be appropriately formed (coarselycomposite state). In addition, a plurality of aggregates in theabove-described densely composite state (primary aggregates) may begathered to form a secondary aggregate in which appropriate gaps areformed among the primary aggregates. The shape of composite pigmentparticles may be any shape, and the composite pigment particles may havevarious shapes such as a spherical shape, a substantially sphericalshape, a columnar shape, needle shape, a spindle shape, an ellipticalshape, a cube, a rectangular solid and an indefinite shape, but aspherical shape, a substantially spherical shape and the like are morepreferable.

In the composite pigment of the present invention, the inorganiccompound is required to exist at least between extender pigmentparticles for performing the function of the inorganic compound(function of fixing extender pigments each other), and in addition, theinorganic compound may exist in such a manner as to cover a part or allof the surfaces of composite pigment particles.

Preferably, the composite pigment of the present invention has adiameter on cumulative 50% (D50) of 1 to 15 μm in a volume cumulativedistribution as measured by a laser diffraction/scattering-type particlesize distribution measuring apparatus. For measurement of the volumeparticle size distribution of the composite pigment, for example, alaser diffraction/scattering-type particle size distribution measuringapparatus (LA-910 manufactured by HORIBA, Ltd.) can be used.

When the value of D50 is in the above-mentioned range, the matte effectin a paint film containing the composite pigment can be exhibited at ahigh level. Specifically, when a clear paint is prepared in a pigmentvolume concentration (PVC) of 20%, and formed into a paint film, and aspecular gloss is measured in accordance with JIS K5600-4-7: 1999, aspecular gloss of 5% or less can be obtained under a geometric conditionof 60°. This means that a gloss is reduced even to the degree of a glossreduction referred to as “matting” over the degree of a gloss reductiongenerally referred to as “70% gloss (specular gloss of 55 to 65% at)60°)”, “50% gloss” or “30% gloss”.

Preferably, the composite pigment of the present invention has adiameter on cumulative 90% (D90) of 5 to 30 μm in a volume cumulativedistribution as measured by a laser diffraction/scattering-type particlesize distribution measuring apparatus. In this way, so-called “85°gloss” can also be sufficiently reduced in a paint film containing thecomposite pigment. Specifically, the specular gloss under a geometriccondition of 85°, which is obtained by preparing a clear paint in apigment volume concentration (PVC) of 20%, forming the paint into apaint film, and performing measurement in accordance with JIS K5600-4-7:1999, can be reduced to 10% or less.

In addition, when the composite pigment of the present invention isblended in a paint film, the paint film has a good (smooth) tactilefeeling, and the diameter on cumulative 90% (D90) is preferably 30 μm orless because a sufficiently smooth tactile feeling of the paint film canbe attained. From the viewpoint of the tactile feeling of the paintfilm, the diameter on cumulative 90% (D90) is more preferably 20 μm orless.

As an evaluation index for the tactile feeling of the paint film, forexample, a friction coefficient of the paint film can be used, and asthe friction coefficient, a MIU (mean friction coefficient), an MMD(mean friction coefficient variation) and the like can be used. Thesefriction coefficients can be measured using, for example, a frictionfeeling tester (KES-SE manufactured by Kato Tech Co., Ltd.).

When the composite pigment of the present invention has a diameter oncumulative 90% (D90) of 20 μm or less, the value of the MMD (meanfriction coefficient variation) can be set to 0.02 or less, preferably0.01 or less.

Preferably, the composite pigment of the present invention has an oilabsorption of 80 (ml/100 g) or less as measured by the method describedin JIS K 5101-13-1. In this way, an increase in viscosity of a paintcontaining the composite pigment of the present invention can besufficiently reduced. From the viewpoint of reduction of the viscosity(improvement of handling) of the paint, the oil absorption is morepreferably 60 (ml/100 g) or less.

The composite pigment of the present invention may further have aninorganic compound and/or organic compound for surface treatment on theouter surface thereof in addition to the above-mentioned configuration.Since the inorganic compound and/or organic compound exists on thesurface of the composite pigment of the present invention (specifically,the inorganic compound and/or organic compound exists in such a manneras to cover a part or the whole of the surface of the compositepigment), and is used for so-called “surface treatment of compositepigment”, the inorganic compound and/or organic compound is different infunction from the above-mentioned inorganic compound and organiccompound to be used for fixation (also referred to as an “inorganiccompound and/or organic compound for fixation”). Thus, here, the“inorganic compound and/or organic compound for surface treatment” isappropriately distinguished from the “inorganic compound and/or organiccompound for fixation”.

When the expression “for fixation” or “for surface” is absent, and it isnot possible to guess from the surrounding words, normally the inorganiccompound and/or organic compound for fixation is suggested.

Examples of the inorganic compound for surface treatment include oxides,hydroxides and hydrous oxides of silicon, aluminum, zirconium, antimony,tin, cerium, zinc, titanium and the like. More specifically, silica,aluminum oxide, aluminum hydroxide, zirconium oxide, antimony oxide, tinoxide, cerium oxide, zinc oxide, titanium oxide and the like can beused. By treating the composite pigment with the inorganic compound,acid resistance and weatherability can be improved, or dispersibility ina dispersion medium such as a resin or the like can be improved.

Examples of the organic compound for surface treatment, which isprovided on the surface of the composite pigment of the presentinvention, include organic silicon compounds such as silicone resins,siloxanes, silane coupling agents, carboxylic acids such as stearic acidand lauric acid, polyols and amines. By treating the matting agent withthe organic compound, dispersibility in a dispersion medium such as aresin or the like can be improved.

The composite pigment of the present invention can be produced by, forexample, the following method. That is, an extender pigment and aninorganic compound source are added to a solvent such as water, anddispersed by a disperser or the like to form a slurry.

The “inorganic compound source” in the present invention means amaterial which is precipitated as an inorganic compound by adjustment ofthe pH of a slurry as described later. Examples of the inorganiccompound source include sodium silicate, sodium aluminate, aluminumsulfate, zirconium sulfate, stannous chloride and titaniumtetrachloride. The inorganic compound source is preferably sodiumsilicate. As the sodium silicate, sodium silicates No. 1, No. 2 and No.3 as specified in JIS 1408-1966 can be all used, but use of sodiumsilicate No. 3 is preferable from the viewpoint of availability andhandling.

Here, in preparation of the slurry, it is preferable that the volumeratio (Va/Vb) of the volume (Va) of the inorganic compound source to thevolume (Vb) of the extender pigment is set to 0.1 to 3. Here, the volume(Va) of the inorganic compound source means a volume calculated in termsof the volume of an inorganic compound precipitated as a result ofadjustment of the pH as described later. When the volume ratio is in theabove-mentioned range, a sufficient fixation effect by the inorganiccompound can be obtained, so that the composite pigment has anappropriate size (preferred particle size distribution).

Subsequently, the pH of the slurry is adjusted to precipitate aninorganic compound derived from the inorganic compound source, andextender pigment is fixed with the inorganic compound.

When sodium silicate is used as the inorganic compound source, it ispreferable that the pH is adjusted to 2 to 10 by adding dilute sulfuricacid while the slurry is heated to be held at about 50 to 100° C. Inthis way, it is possible to obtain a composite pigment having anappropriate size (preferred particle size distribution) while reducingformation of free silica. In adjustment of the pH by addition of dilutesulfuric acid as described above, it is more preferable to adjust the pHwithin a range of 6 to 9, and it is still more preferable to adjust thepH within a range of 7 to 8.

When aluminum sulfate is used as the inorganic compound source, it ispreferable that the pH is adjusted to 4 to 13 by adding caustic soda(sodium hydroxide) while the slurry is heated to be held at about 50 to100° C.

Subsequently to the above-described step, the resulting pigment can bedehydrated and washed, dried, and appropriately ground by known methodsas necessary. Further, the pigment dried as described above may becalcined at a higher temperature as necessary. The calcinationtemperature can be appropriately set, and for example, a temperature ofabout 300 to 900° C. is preferable.

A method including fixing the extender pigment with an inorganiccompound has been described above, but it is also possible to fix theextender pigment with an organic compound. Specifically, the extenderpigment and an organic compound (organic flocculant, organic coagulantor the like including a polymer compound such as a cationic polymer, ananionic polymer or a nonionic polymer) are added to a solvent such aswater, and dispersed by a disperser or the like to form a slurry, andthe extender pigment is fixed. In this way, it is possible to produce acomposite pigment in which an extender pigment is fixed with an organiccompound.

The composite pigments of the present invention, which have beenproduced by the various methods described above, may be subjected toclassification for the purpose of removing coarse particles. Theclassification can be performed by grinding or sieving. The method forclassification by grinding is not particularly limited, and examplesthereof may include use of an atomizer. Examples of the method forclassification by sieving may include wet classification and dryclassification.

When the composite pigment of the present invention is further subjectedto surface treatment with an inorganic compound and/or organic compoundfor surface treatment, the surface treatment can be performed using aknown method such as a wet process or a dry process. Here, it ispreferable that a method involving application of a high torque isavoided so that the prepared composite pigment is not broken. Forexample, in the wet process, water or an organic solvent is added to thecomposite pigment of the present invention and the inorganic compoundand/or organic compound, and the resulting mixture is mixed, whereby thematting agent according to the present invention can be subjected tosurface treatment with the inorganic compound and/or organic compound.

The composite pigment of the present invention can be used for variousapplications. For example, the composite pigment is appropriately usedas a matting agent to be blended in a paint composition for coating ofbuilding wall surfaces (exteriors, interiors, ceilings, floors, and wallsurfaces, floors and the like of baths, kitchens, lavatories and thelike), coating of building materials, coating of vehicles, coating offurniture, coating of electric and mechanical products and the like. Inaddition, the composite pigment of the present invention can be blendedas a matting agent in plastic, rubber, latex, elastomer and the like.When the composite pigment of the present invention is used as a mattingagent, the composite pigment can be used as such, or mixed with aconventional matting agent, a color material, an additive and the like,and used. Further, the composite pigment of the present invention can beblended in various paint compositions, plastic, rubber, latex,elastomer, ceramic, glass, metal or the like as an extender, anadditive, a filler, an extender pigment, a flowability imparting agent,a strength auxiliary agent, an optical property improver or the like.

A paint composition of the present invention contains the compositepigment and a resin, and contains a color material, a dispersant, anadditive, a solvent and the like as necessary.

Examples of the resin contained in the paint composition of the presentinvention include various paint resins such as phenol resins, alkydresins, acrylic alkyd resins, acrylic resins, acrylic emulsion resins,polyester resins, polyester urethane resins, polyether resins,polyolefin resins, polyurethane resins, acrylic urethane resins, epoxyresins, modified epoxy resins, silicone resins, acrylic silicone resinsand fluororesins.

As the color material, a pigment, a dye or the like can be used. As thepigment contained in the paint composition of the present invention,various inorganic pigments (titanium dioxide, zinc oxide, basic leadcarbonate, lower titanium oxide, titanium oxynitride (titanium black),carbon black, bone black (bone charcoal), graphite, iron black, cobaltchromate black spinel, iron chromate composite oxide, copper chromatespinel black composite oxide, Fe—Mn—Bi black, red iron oxide, molybdenumred, nickel antimony titanium yellow, chrome antimony titanium buff,synthetic iron oxide yellow, chrome yellow, ultramarine blue, iron blue,cobalt blue, cobalt green, chrome green, chromium oxide green, cobaltchromate green spinel, cobalt titanate green spinel and the like); andvarious organic pigments (lake red 4R, ITR red, naphthol red, pyrazoloneorange, pyrazolone red, benzimidazolon orange, watching red, lake red R,Bordeaux 10B, Bon maroon light, anthraquinone red, dianthraquinone red,anthanthrone red, anthanthrone orange, perylene red, perylene maroon,perylene violet, perinone orange, quinacridone red, quinacridone violet,quinacridone magenta, dimethyl magenta, dichloroquinacridone magenta,dichloro-magenta, quinacridone maroon, quinacridone scarlet,diketo-pyrrolo-pyrrole, fast yellow, benzimidazolon yellow, diarylideyellow, isoindolin yellow, quinophthalone yellow, phthalocyanine green,chlorinated phthalocyanine green, brominated phthalocyanine green,phthalocyanine blue, threne blue, dioxazine violet and the like) can beused. As the dye, basic dyes (rhodamine, Bismarck green, malachitegreen, methyl violet and the like); direct dyes (congo red, directscarlet and the like); acidic dyes (metanil yellow, nigrosin, acid fastred and the like); metal-containing complex salt dyes; oil-soluble dyes;and the like can be used. At least one selected from these colormaterials can be used.

In addition, when a color material is not blended in the paintcomposition, a transparent (translucent) matting paint can be obtained.The transparent (translucent) matting paint can be used as a top coatwhich is applied onto a base layer (layer formed by applying a colorgloss paint, a pearl paint or the like to a base material) in vehicleapplications or the like.

Examples of the additive contained in the paint composition of thepresent invention include an emulsifier, an antifreezing agent, a pHadjuster, a thickener and a defoaming agent generally used. Examples ofthe solvent include water, toluene, xylene, mineral spirit, acetone,methyl ethyl ketone, methanol, butanol, ethyl acetate, amine acetate andethylene glycol. The dispersant is appropriately selected according tothe type of an inorganic compound used in synthesis of the compositepigment. For example, when silica is used as the inorganic compound, thesurface of the composite pigment is slightly acidic because silicaexists on the surface of the composite pigment. Here, it is preferablethat as the dispersant, a dispersant having an amine value is used.Specific examples thereof include “DISPERBYK (registeredtrademark)-183”, “DISPERBYK (registered trademark)-184” and “DISPERBYK(registered trademark)-185” manufactured by BYK Additives & Instruments.

The paint composition of the present invention can be prepared bystirring the composite pigment and the resin, and as necessary, thecolor material, dispersant, additive, solvent, and the like by adispersing machine, and as necessary, defoaming the resulting mixture.

When the paint composition of the present invention is formed into acolor matting paint by, for example, addition of the composite pigmentof the present invention to a gloss paint, the amount of the compositepigment added is preferably 0.1 to 10% by mass, more preferably 1 to 5%by mass.

When the paint composition is formed into a transparent (translucent)topcoat matting paint by setting the content of the color material to avery small amount, or avoiding inclusion of a color material, thepigment volume concentration (PVC) of the composite pigment ispreferably in a range of 5 to 40%, more preferably in a range of 10 to30%, still more preferably in a range of 15 to 25%. When the pigmentvolume concentration (PVC) is in the above-mentioned range, a topcoatmatting paint can be obtained which makes it possible to sufficientlyreduce a gloss while maintaining color of a base layer.

A paint film of the present invention is the paint composition appliedto a target, and cured. That is, the paint composition is applied to atarget using a brush/wool roller or the like, and dried, whereby thepaint film of the present invention can be obtained. Examples of thetarget include building materials (concrete, mortar, gypsum, plaster,plastic, glass, earthenware, stone, wood and the like), vehicle mainbodies (made of metal or plastic), furniture and electric and mechanicalproducts (made of plastic, glass, earthenware, stone, wood or the like).The target may be coated in advance with a paint composition (glosspaint, pearl paint or the like) which is different from the paintcomposition of the present invention.

Embodiment of the Present Invention (the Second Invention of the PresentApplication)

A composite pigment of the present invention is a composite pigment inwhich at least a titanium oxide pigment and an extender pigment arefixed with an inorganic compound and/or organic compound.

The composite pigment of the present invention is in the form in whichat least a titanium oxide pigment and an extender pigment are fixed withan inorganic compound and/or organic compound. Although the compositepigment may have various forms, the forms typically include a form inwhich at least a plurality of titanium oxide pigment particles and aplurality of extender pigment particles are fixed with an inorganiccompound and/or organic compound. At this time, it is preferable thatconstituent particles of the same kind (titanium oxide pigment particleseach other or extender pigment particles each other) do not exist in astate of huddling in specific positions, but a state in which theextender pigment particles exist between the titanium oxide pigmentparticles is preferable. The extender pigment particles perform thefunction of a spacer so that the low-gloss property (matte effect) andthe hiding power can be improved. Of course, the extender pigmentparticles are not always required to exist between all the titaniumoxide pigment particles, and regions where the constituent particles ofthe same kind exist in a huddling state may be formed in a part ofregions of the composite pigment, but when the composite pigment ismacroscopically viewed, it is preferably to have a form in which theplurality of the titanium oxide pigment particles and the extenderpigment particles exist in an evenly dispersed state.

Then from the viewpoint that the plurality of the titanium oxide pigmentparticles and the extender pigment particles are disposed in adispersion state in the composite pigment, it is preferable that theshape of the titanium oxide pigment particles and/or extender pigmentparticles is spherical or substantially spherical.

Here, as described above, to facilitate having the state that theplurality of the titanium oxide pigment particles and the extenderpigment particles exist in an evenly dispersed state, it is preferablethat the average primary particle diameter of the extender pigmentparticles is nearly equal to or smaller than the average primaryparticle diameter of the titanium oxide particles. Specifically, whenthe average particle diameter of the titanium oxide particles is takenas 1, the average primary particle diameter of the extender pigmentparticles is preferably 0.1 to 1.5 and more preferably 0.5 to 1. This isbecause thus using the extender pigment particles nearly equal to orsmaller than the titanium oxide pigment particles makes it easy for theextender pigment particles to function as a spacer between the titaniumoxide pigment particles.

The average primary particle diameter can be measured by the same methodas electron microscopy used for the measurement of the average primaryparticle diameter, already described in the above-mentioned [Embodimentof the present invention (the first invention of the presentapplication)].

Then the titanium oxide pigment particles and the extender pigmentparticles may be in a state of having almost no gaps (densely compositestate) therebetween due to an inorganic compound and/or organiccompound, or may be in a state of having gaps (coarsely composite state)appropriately formed therebetween. In addition, a plurality ofaggregates in the above-described densely composite state (primaryaggregates) may be gathered to form a secondary aggregate in whichappropriate gaps are formed among the primary aggregates. The shape ofthe composite pigment particles may be any shape and may have variousshapes such as a spherical shape, a substantially spherical shape, acolumnar shape, a needle shape, a spindle shape, an elliptical shape, acube, a rectangular solid and an indefinite shape, but a sphericalshape, a substantially spherical shape or the like is more preferable.

In the composite pigment of the present invention, the inorganiccompound and/or organic compound fixes the constituent particles (thetitanium oxide pigment particles, the extender pigment particles and thelike) of the composite pigment. Therefore, the inorganic compound and/ororganic compound, though being required to exist at least between theconstituent particles, may exist so as further to cover a part or thewhole of the surfaces of the composite pigment (specifically, thesurfaces of the composite pigment particles). In this case, payingattention to functions of the both, the former (the inorganic compoundand/or organic compound to be used for fixing the constituent particlesof the composite pigment) and the latter (the inorganic compound and/ororganic compound existing so as to cover a part or the whole of thesurfaces of the composite pigment, that is, to be used for so-called“surface treatment of the composite pigment”) are appropriatelydistinguished from each other by referring the former as an “inorganiccompound and/or organic compound for fixation” and the latter as an“inorganic compound and/or organic compound for surface treatment”.

Here, when the expression “for fixation” or “for surface treatment” isabsent, and it is not possible to guess which one from the context, “forfixation” is usually meant.

In the composite pigment particles of the present invention, thediameter on cumulative 90% (D90) (diameter on cumulative 90% in thevolume cumulative distribution) measured by a laserdiffraction/scattering-type particle size distribution measuringapparatus is preferably 20 μm or less and more preferably 10 μm or less.

The diameter on cumulative 90% (D90) of the composite pigment particlescan be measured by using a laser diffraction/scattering-type particlesize distribution measuring apparatus. As such an apparatus, there canbe used, for example, a laser diffraction/scattering-type particle sizedistribution measuring apparatus “LA-910” (manufactured by HORIBA,Ltd.).

Usual flat emulsion paints develop the matte effect, whereas the surfaceof their paint films is coarse. As a result, the tactile feeling of thepaint film becomes rough and stain is liable to be attached on the paintfilms and the stain can hardly be removed in many cases. By contrast,when there is used the composite pigment of the present invention havinga diameter on cumulative 90% (D90) of 20 μm or less, since the paintfilm surface becomes smooth, such a unique design can be developed thatwhile the low-gloss property (matte effect) is developed, the tactilefeeling of the paint films is smooth. At the same time, a functionalitycan be imparted such that stain is hardly attached to the paint filmsand the stain is easily removed.

In the composite pigment particles of the present invention, the mediandiameter D50 (diameter on cumulative 50% in the volume cumulativedistribution) measured by the laser diffraction/scattering-type sizedistribution measuring apparatus is preferably 1 to 10 μm and morepreferably 1 to 3 By forming the composite pigment of the presentinvention into a paint and using it, the surface of the paint film canfurther be made smooth. As a result, while the low-gloss property (matteeffect) is developed, the smoothness of tactile feeling of the paintfilm and the difficulty in attachment of stain on the paint film (easein removal of the stain) are more improved.

The median diameter D50 of the composite pigments can be measured, as inthe above-mentioned D90, by using the laser diffraction/scattering-typeparticle size distribution measuring apparatus “LA-910” (manufactured byHORIBA, Ltd.), or the like.

For the titanium oxide pigment particles forming the composite pigmentof the present invention, the average primary particle diameter ispreferably 0.1 to 1.0 more preferably 0.1 to 0.5 μm and still morepreferably 0.1 to 0.3 By making the average primary particle diameter ofthe titanium oxide pigment particles in the above range, when thetitanium oxide pigment and the extender pigment are combined, thecomposite pigment can be made to have an appropriate size. This ispreferable because, as a result, the low-gloss property (matte effect)and the hiding power can be improved and the tactile feeling of thepaint film can be made smoother

The shape of the titanium oxide pigment particles may be any shape andmay have various shapes such as a spherical shape, a substantiallyspherical shape, a columnar shape, a needle shape, a spindle shape, anelliptical shape, a cube, a rectangular solid and an indefinite shape.

As the crystal form of the titanium oxide pigment, any form of anatasetype, rutile type and brookite type can be used, but use of the rutiletype or the anatase type is preferable. When the composite pigment isblended in a paint resin or the like, from the viewpoint of reducing thedeterioration of the paint resin due to the photocatalytic activity, useof the rutile type is preferable. Here, as titanium oxide particles,there can be used ones produced by either method of so-called sulfateprocess or chloride process.

The extender pigment constituting the composite pigment of the presentinvention includes calcium carbonate (light calcium carbonate, heavycalcium carbonate, precipitated (synthetic) calcium carbonate, and thelike), barium sulfate (precipitated (synthetic) barium sulfate, and thelike), barite powder, talc, kaolin, clay, aluminum hydroxide and whitecarbon. As the extender pigment, calcium carbonate and barium sulfateare preferable.

As described later, in the composite pigment of the present invention,the extender pigment particles enter between the titanium oxide pigmentparticles and function as a spacer to provide appropriate gaps betweenthe particles. To realize such a function, the volume of the extenderpigment is important. In this point, calcium carbonate has a relativelylow specific gravity and can secure a sufficient volume even in a smalluse amount thereof. Therefore, from the viewpoint of the cost, it ismore preferable to use calcium carbonate as the extender pigment. Amongcalcium carbonate, precipitated (synthesized) calcium carbonate isespecially preferable. This is because the precipitated (synthesized)calcium carbonate is easy in designing its particle size in a desiredone and a precipitated (synthesized) calcium carbonate having thedesired particle size is easily available.

In the extender pigment forming the composite pigment of the presentinvention, its average primary particle diameter is preferably 0.1 to1.0 μm, more preferably 0.1 to 0.5 μm and still more preferably 0.1 to0.35 μm. Making the average primary particle diameter of the extenderpigment in the above range is preferable because of, when the titaniumoxide pigment and the extender pigment are combined, enabling thecomposite pigment particles to be formed into an appropriate size, andenabling the low-gloss property (matte effect) and the hiding power tobe improved and the tactile feeling of the paint film to becomesmoother.

The shape of the extender pigment particle may be any shape and may havevarious shapes such as a spherical shape, a substantially sphericalshape, a columnar shape, a needle shape, a spindle shape, an ellipticalshape, a cube, a rectangular solid and an indefinite shape.

In the composite pigment of the present invention, the content ratio ofthe extender pigment to the titanium oxide pigment can be appropriatelyset, but when the mass of the titanium oxide is taken as 1 in massratio, the mass of the extender pigment is preferably 0.01 to 100, morepreferably 0.1 to 10 and still more preferably 0.2 to 1.

To firmly fix the titanium oxide pigment and the extender pigment, aninorganic compound and/or organic compound is used. Examples of theinorganic compound include oxides, hydroxides and hydrated oxides ofsilicon, aluminum, zirconium, antimony, tin, cerium, zinc. Morespecifically, there can be used silica, aluminum oxide, aluminumhydroxide, zirconium oxide, antimony oxide, cerium oxide, zinc oxide andthe like.

As the inorganic compound, from the viewpoint of reducing the increaseof the specific surface area of the composite pigment and the increaseof the oil absorption along therewith, it is preferable to use silica.The increase in the viscosity of a paint when the paint is formed can bereduced thereby.

In the composite pigment of the present invention, when the inorganiccompound is used for the fixation (that is, when the inorganic compoundfor fixation is used), the content ratio by mass of the inorganiccompound to the pigment components (titanium oxide, the extender pigmentand the like) is, when the mass of the pigment components is taken as 1,preferably 0.01 to 100, more preferably 0.05 to 10 and still morepreferably 0.1 to 0.5.

As the organic compound for fixation constituting the composite pigmentof the present invention, organic flocculants, organic coagulants andthe like can be used. The organic flocculants and the organic coagulantsare not especially limited as long as being capable of catching andaggregating a plurality of particles by their polymer chains, andpolymer compounds such as cationic polymers, anionic polymers andnonionic polymers can be used. The content ratio to the organic compoundcan be appropriately set, but is, when the mass of the pigmentcomponents is taken as 1 in mass ratio, preferably 0.001 to 1, morepreferably 0.001 to 0.1 and still more preferably 0.01 to 0.05.

The composite pigment of the present invention may have an inorganiccompound and/or organic compound for surface treatment on its surface.As described above, these inorganic compound and/or organic compound,since existing so as to cover a part or the whole of the surface of thecomposite pigment of the present invention, that is, being used forso-called “surface treatment of the composite pigment”, have a functiondifferent from the “inorganic compound and/or organic compound forfixation”. Hence, here, the “inorganic compound and/or organic compoundfor surface treatment” and the “inorganic compound and/or organiccompound for fixation” are distinguished from each other.

Examples of such an inorganic compound for surface treatment includethose exemplified as inorganic compounds for surface treatment in theabove-mentioned [Embodiment of the present invention (the firstinvention of the present application)], as they are.

Further the organic compound for surface treatment made to exist on thesurface of the composite pigment of the present invention includes thoseexemplified as organic compounds for surface treatment in theabove-mentioned [Embodiment of the present invention (the firstinvention of the present application)], as they are, and by treating thecomposite pigment with these organic compounds for surface treatment,the dispersibility to a disperse medium such as a resin can be improved.

The composite pigment of the present invention may be blendedappropriately, in addition to the titanium oxide pigment and theextender pigment, as required, with various functional pigments such ascolor pigments, organic pigments, organic dyes and heat shield pigments.

The composite pigment of the present invention can be produced byvarious well-known methods, and can also be granulated by a granulatingmachine, but a fine composite pigment can hardly be produced. Then, amethod in which a slurry containing, at least, the titanium oxidepigment, the extender pigment and the inorganic compound and/or organiccompound is prepared and under stirring, at least, the titanium oxidepigment and the extender pigment are fixed with the inorganic compoundand/or organic compound, is a preferred method because of being capableof easily producing a fine composite pigment having a median diameterD50 and a diameter on cumulative 90% (D90) in the above ranges.

Specifically, the titanium oxide pigment and the extender pigment(calcium carbonate, barium sulfate and the like) and the like and theinorganic compound and/or organic compound are added to a solvent suchas water, and dispersed by a disperser to make a slurry. As theinorganic compound, sodium silicate is preferable, and any of No. 1, No.2 and No. 3 specified in JIS 1408-1966 can be used, but from the pointof easy availability and handling, it is preferable to use No. 3. Whilethe slurry is heated and held at about 50 to 100° C., a dilute sulfuricacid is added to adjust pH. At this time, the pH value to be adjusted atdepends on the extender pigment to be used. For example, when calciumcarbonate is used as the extender pigment, pH is adjusted at about 7.0to 10.0. When barium sulfate is used as the extender pigment, pH isadjusted at about 3.0 to 10.0. As a result, there can be obtained in asolution the composite pigment in which pluralities of the titaniumoxide pigment particles and extender pigment particles are fixed withthe inorganic compound and/or organic compound. To obtain the compositepigment having a more appropriate size, it is preferable that pH isadjusted in the range of 7.0 to 7.5. Thereafter, as required, thepigment is dehydrated and washed, dried and appropriately ground to beable to produce the composite pigment of the present invention. Furtheras required, the dried pigment in the above may be calcined at a highertemperature. The calcination temperature can be appropriately set, andfor example, about 300 to 900° C. is preferable.

The composite pigment of the present invention produced by variouswell-known methods may be classified for the purpose of removing coarseparticles. The classification can be performed by grinding or sieving.The classification method by grinding or sieving can be performed by thesame method as the classification method already described in theabove-mentioned [Embodiment of the present invention (the firstinvention of the present application)]

When the composite pigment of the present invention is subjected to asurface treatment with the inorganic compound and/or organic compoundfor surface treatment, the surface treatment can be performed by awell-known method such as a wet process or a dry process, and apreferred embodiment at this time is as described in [Embodiment of thepresent invention (the first invention of the present application)].

The composite pigment of the present invention can be used as a whitepigment (matting pigment) having the low-gloss property (matte effect)in various applications. The composite pigment is appropriately used,for example, as a pigment for coating of building wall surfaces(exteriors, interiors, ceilings, floors, and wall surfaces, floors andthe like of baths, kitchens, lavatories and the like), a pigment forcoating of building materials, a pigment for coating of vehicles, apigment for coating of furniture and a pigment for coating of electricand mechanical products. Further such a matting pigment can also be usedby being blended in various paints in place of so-called mattingmaterials.

The paint composition of the present invention contains theabove-mentioned composite pigment, and contains, in addition to thecomposite pigment, as required, a resin, a dispersant, an additive, asolvent and the like. Examples of the resin include the resins, as theyare, exemplified as resins contained as the paint composition in theabove-mentioned [Embodiment of the present invention (the firstinvention of the present application)]. The additive includes variousones usually used, such as an emulsifier, an antifreezing agent, a pHadjuster, a thickener and a defoaming agent. The solvent includes water,toluene, xylene, mineral spirit, acetone, methyl ethyl ketone, methanol,butanol, ethyl acetate, amine acetate and ethylene glycol. Thedispersant is selected according to the type of the inorganic compoundand/or organic compound to be used in fabrication of the compositepigment. For example, when silica is used for the above-mentionedcomposite pigment, the surface condition of the composite pigment isslightly acidic because silica exists on the surface thereof. In thiscase, it is more preferable that as the dispersant, a dispersant havingan amine value is used.

The paint composition of the present invention can be prepared bystirring the composite pigment, and as necessary, the above-mentionedresin, dispersant, additive and solvent, and the like by a dispersingmachine, and as necessary, defoaming the resulting mixture.

In the paint composition of the present invention, it is preferable thatthe pigment volume concentration (PVC) is adjusted in the range of 30%to 60%. When attaching importance to reducing the gloss of a paint film,it is more preferable that the pigment volume concentration is made tobe on the lower limit side of the above range, specifically, 30 to 40%.Then when attaching importance to enhancing the hiding power of a paintfilm, it is more preferable that the pigment volume concentration ismade to be on the upper limit side of the above range, specifically, 50to 60%.

The paint film of the present invention is a paint film made by applyingand curing the above-mentioned paint composition on a substrate. Thatis, the paint film of the paint according to the present invention canbe obtained by applying the above-mentioned paint composition on asubstrate by using a brush, a wool roller or the like, and drying theresultant. The substrate includes building materials (concrete, mortar,gypsum, plaster, plastic, glass, earthenware, stone, wood and the like),vehicle main bodies (made of metal or plastic), furniture and electricand mechanical products (made of plastic, glass, earthenware, stone,wood or the like).

Embodiment of the Present Invention (the Third Invention of the PresentApplication)

The composite pigment of the present invention is one in which aninorganic color pigment is fixed by an inorganic compound, and aplurality of particles of the inorganic color pigment are aggregatedinto a granule by means of an inorganic compound.

In the present invention, “inorganic color pigment” refers to a pigmentwhich contains an inorganic compound as a main component and exhibits anachromatic color such as white or black, or a chromatic color such asred, yellow, or blue. Examples of a white inorganic color pigmentinclude titanium dioxide, zinc oxide, and basic lead carbonate. Examplesof a black inorganic color pigment include a lower titanium oxide,titanium oxynitride (titanium black), carbon black, bone black (bonecharcoal), graphite, iron black, cobalt chromate black spinel, ironchromate composite oxide, copper chromate spinel black composite oxide,and Fe—Mn—Bi black. Examples of a red inorganic color pigment includered iron oxide, and molybdenum red. Examples of a yellow inorganic colorpigment include nickel antimony titanium yellow, chrome antimonytitanium buff, synthetic iron oxide yellow, and chrome yellow. Examplesof a blue inorganic color pigment include ultramarine blue, iron blue,and cobalt blue. Examples of a green inorganic color pigment includecobalt green, chrome green, chromium oxide green, cobalt chromate greenspinel, and cobalt titanate green spinel. At least one kind selectedfrom these inorganic color pigments may be used.

When titanium dioxide is used as the inorganic color pigment, withrespect to the crystal form of a titanium dioxide pigment, any ofanatase-type, rutile type, and brookite type may be used, but it ispreferable to use a rutile type, or an anatase-type. When a compositepigment is added to a paint resin or the like, it is more preferable touse a rutile type from the viewpoint of reducing deterioration of thepaint resin due to photocatalytic activities. In this regard, astitanium dioxide particles, those produced by either of so-calledsulfate process or chloride process may be used.

The size of inorganic color pigments constituting the composite pigmentof the present invention is preferably 0.1 to 1.0 μm in terms of anaverage primary particle diameter, more preferably 0.15 to 0.7 andfurther preferably 0.2 to 0.5 In a case where the average primaryparticle diameter of the inorganic color pigment is within the aboverange, when the inorganic color pigments are fixed by an inorganiccompound and/or organic compound to form a composite, the compositepigment can have an appropriate size (preferable particle sizedistribution).

The average primary particle diameter can be measured by the same methodbased on the electron microscopic method used for measuring the averageprimary particle diameter as described in the above [Embodiment of thepresent invention (the first invention of the present application)].

There is no particular restriction on the shape of the inorganic colorpigment, and it may be any of a spherical shape, a substantiallyspherical shape, a columnar shape, a needle shape, a spindle shape, anelliptical shape, a cubic shape, a rectangular solid shape, and anindefinite shape.

Examples of an inorganic compound used for firmly fixing the inorganiccolor pigment include oxides, hydroxides, and hydrous oxides of silicon,aluminum, zirconium, antimony, tin, cerium, zinc, titanium, and thelike. More specific examples thereof include silica, aluminum oxide,aluminum hydroxide, zirconium oxide, antimony oxide, tin oxide, ceriumoxide, zinc oxide, and titanium oxide; and at least one selected fromthe inorganic compounds may be used.

As the inorganic compound, an inorganic silicon compound is preferable,and silica is particularly preferable. By using an inorganic siliconcompound, the specific surface area and the oil absorption amount of acomposite pigment can have appropriate values, and a paint containingthe same can be easily handled.

In the case of the composite pigment of the present invention, when aninorganic compound is used for fixing inorganic color pigments, thecontent ratio of the inorganic color pigment to the inorganic compoundis preferably as the following ratio. That is, putting the volume of thepigment component as 1, the volume of the inorganic compound ispreferably 0.3 to 2, more preferably 0.4 to 1.5, and further preferably0.5 to 1.

For fixing the inorganic color pigments, an organic compound having thesame effect as the inorganic compound may be used. As the organiccompound, an organic flocculant, an organic coagulant, or the like maybe used. There is no particular restriction on the organic flocculant,and the organic coagulant, insofar as they are capable of catching andaggregating a plurality of particles with their polymer chains, and apolymer compound such as a cationic polymer, an anionic polymer, and anonionic polymer may be used. The content of the organic compound can beset appropriately.

The composite pigment of the present invention takes the form of anaggregate in which the inorganic color pigment particles are fixed by aninorganic compound and/or organic compound. At this time, there may bealmost no gaps among the inorganic color pigment particles (denselycomposite state), or may be appropriate gaps (coarsely composite state).In addition, a plurality of aggregates in the above-described denselycomposite state (primary aggregates) may be gathered to form a secondaryaggregate in which appropriate gaps are formed among the primaryaggregates. The composite pigment may have any shape, such as aspherical shape, a substantially spherical shape, a columnar shape, aneedle shape, a spindle shape, an elliptical shape, a cubic shape, arectangular solid shape, and an indefinite shape, however the sphericalshape, the substantially spherical shape, or the like is morepreferable.

In the composite pigment of the present invention, an inorganic compoundand/or organic compound is required to be present at least among theinorganic color pigment particles in order to exert its function (thefunction of fixing the inorganic color pigment particles each other),and further the inorganic compound and/or organic compound may be sopresent as to cover part or all of the surfaces of the compositepigment. In this case, paying attention to both the functions, theformer (an inorganic compound and/or organic compound used for fixingthe inorganic color pigment particles each other) is referred to as an“inorganic compound and/or organic compound for fixation”, and thelatter (an inorganic compound and/or an organic compound present so asto cover part or all of the surfaces of the composite pigment, and usedfor so-called “surface treatment of composite pigment”) is referred toas an “inorganic compound and/or organic compound for surfacetreatment”, and the two are appropriately distinguished from each otherthereby. In this regard, when there is no notation such as “forfixation” or “for surface treatment”, and it cannot be judged from thecontext, it is normally regarded as “for fixation”.

The composite pigment of the present invention has a specific particlesize distribution. That is, in the volume cumulative distributionmeasured by a laser diffraction/scattering-type particle sizedistribution measuring apparatus, the abundance ratio of the compositepigment particles having a particle diameter of 1 μm or more is 50% ormore of the total, and the diameter on cumulative 90% (D90) is 30 μm orless.

For measurement of the volume particle size distribution of thecomposite pigment, for example, a laser diffraction/scattering-typeparticle size distribution measuring apparatus “LA-910” (manufactured byHORIBA, Ltd.) may be used.

When the abundance ratio of the composite pigment particles having aparticle diameter of 1 μm or more is 50% or more of the total in thevolume cumulative distribution, and the pigment is added in a paint(paint film), the paint film can be made to have a low gloss (a lowluster). Specifically, in a case where a paint is prepared at a pigmentvolume concentration (PVC) of 40%, and this is coated to form a paintfilm, which specular gloss is measured according to JIS K 5600-4-7:1999, the specular gloss under a geometric condition of 60° can bereduced to 5% or less. This means that the gloss is reduced even to thedegree of a gloss reduction referred to as “matting” over the degree ofa gloss reduction generally referred to as “70% gloss (specular gloss of55 to 65% at 60°)”, “50% gloss” or “30% gloss”. Also, the specular glossunder a geometric condition of 85° can be reduced to 40% or less, andso-called 85° gloss can be sufficiently reduced.

With respect to the composite pigment of the present invention, when theabundance ratio of the composite pigment having a particle diameter of 2μm or more is 30% or more of the total in the volume cumulativedistribution measured by a laser diffraction/scattering-type particlesize distribution measuring apparatus, a paint film with a lower gloss(a lower luster) can be favorably realized. By doing so, the speculargloss measured under a geometric condition of 85° according to JIS K5600-4-7: 1999 (so-called 85° gloss) can be reduced to 30% or less.Further, when the abundance ratio of the composite pigment having aparticle diameter of 5 μm or more in the volume cumulative distributionis 20% or more of the total, the specular gloss under a geometriccondition of 85° may be reduced to 10% or less, which is more favorable.

Since the composite pigment of the present invention has a diameter oncumulative 90% (D90) of 30 μm or less in the volume cumulativedistribution, it can exhibit the smooth tactile feeling of the paintfilm. From the viewpoint of the tactile feeling of a paint film, thediameter on cumulative 90% (D90) is preferably 20 μm or less, and morepreferably 15 or less.

As the evaluation index of the tactile feeling of a paint film, forexample, the friction coefficient of the paint film may be used, and theMIU (mean friction coefficient), MMD (mean friction coefficientvariation), or the like may be used as the friction coefficient. Thesefriction coefficients can be measured using, for example, a frictiontester (KES-SE manufactured by Kato Tech Co., Ltd.).

When the diameter on cumulative 90% (D90) of the composite pigment ofthe present invention is made 15 μm or less, the value of MMD (meanfriction coefficient variation) can be made 0.02 or less, and in afavorable case 0.01 or less.

The composite pigment of the present invention may further contain inits outer surface an inorganic compound and/or organic compound forsurface treatment in addition to the above composition. As describedabove, this inorganic compound and/or organic compound are present so asto cover part or all of the surfaces of the composite pigment of thepresent invention, and used for so-called “surface treatment ofcomposite pigment”, therefore its function is different from that of“inorganic compound and/or organic compound for fixation”. Consequently,here, the “inorganic compound and/or organic compound for surfacetreatment” and the “inorganic compound and/or organic compound forfixation” are distinguished from each other.

Examples of such an inorganic compound for surface treatment includeoxides, hydroxides, and hydrous oxides of silicon, aluminum, zirconium,antimony, tin, cerium, zinc, and titanium. More specifically, silica,aluminum oxide, aluminum hydroxide, zirconium oxide, antimony oxide, tinoxide, cerium oxide, zinc oxide, titanium oxide, and the like can beused. By treating the composite pigment with any of these inorganiccompounds, it is possible to improve the acid resistance and theweatherability, or the dispersibility in a dispersion medium such as aresin or the like.

As an organic compound to be present on the surface of the compositepigment of the present invention, the examples of the organic compoundfor surface treatment listed in the above [Embodiment of the presentinvention (the first invention of the present application)] may beapplicable as they are, and by treating the composite pigment with anyof the organic compounds, dispersion of a resin or the like in adispersion medium can be improved.

The composite pigment of the present invention can be produced, forexample, by the following method. That is, an inorganic color pigmentand an inorganic compound source are added to a solvent such as waterand dispersed by a disperser or the like to form a slurry.

The “inorganic compound source” means herein a material, whichprecipitates an inorganic compound able to fix the inorganic colorpigment, by adjusting the pH of a slurry as described later. Examples ofsuch an inorganic compound source include sodium silicate, sodiumaluminate, aluminum sulfate, zirconium sulfate, stannous chloride, andtitanium tetrachloride. Sodium silicate is preferable as the inorganiccompound source. As sodium silicate, any of No. 1, No. 2 and No. 3defined in JIS 1408-1966 can be used, but use of No. 3 is preferablefrom the viewpoint of availability and handling.

In preparing the slurry, the volume ratio (Va/Vb) of the volume (Va) ofthe inorganic compound source to the volume (Vb) of the inorganic colorpigment is set preferably 0.3 to 2. The volume (Va) of the inorganiccompound source means the volume in terms of an inorganic compound to beprecipitated by the pH adjustment described later. When the amount ofthe inorganic compound source in the slurry is too small, a sufficientfixation effect cannot be obtained, and a composite pigment having adesired particle diameter (particle size distribution) cannot beobtained.

The solid content concentration of the slurry containing the inorganiccolor pigment and the inorganic compound source is 75 to 450 g/L, andpreferably 100 to 400 g/L. By adjustment to such a solid contentconcentration, it becomes easy to obtain a composite pigment having adesired particle size distribution described above.

Subsequently, by adjusting the pH of the slurry, the inorganic colorpigment is fixed by precipitation of an inorganic compound derived fromthe inorganic compound source.

When sodium silicate is used as the inorganic compound source, it ispreferable to heat the slurry and to add dilute sulfuric acid to adjustthe pH between 2 and 10, while keeping the temperature in a range ofabout 50 to 100° C. By doing so, it is possible to obtain in a solutiona composite pigment in which a plurality of inorganic color pigmentparticles are fixed by silica. In this case, as the pH becomes lower,free silica not combined with the inorganic color pigment tends toprecipitate and the amount of the free silica contained in the compositepigment increases. As a result, the viscosity tends to increase when thecomposite pigment is formed into a paint. In this case, as the pHbecomes higher, (specifically, when the pH is around 9 to 10), theparticle diameter of the composite pigment tends to become smaller, andthe matte effect tends to become lower. For this reason, in the pHadjustment by adding the dilute sulfuric acid, the pH is preferablyadjusted into a range of 6 to 9, and more preferably adjusted into arange of 7 to 8.

When aluminum sulfate is used as the inorganic compound source, it ispreferable to heat up the slurry and adjust the pH to 4 to 13 by addingcaustic soda (sodium hydroxide) while keeping the temperature in a rangeof about 50 to 100° C.

Following the above steps, if necessary, it is possible to performwashing and dehydration, drying, and appropriate grinding by a publiclyknown method. Further, if necessary, the above dried product may becalcined at a higher temperature. The calcination temperature can beappropriately set, for example, preferably at about 300 to 900° C.

In the above, the method of fixing the inorganic color pigment using aninorganic compound has been described, however it is also possible tofix the inorganic color pigment by an organic compound. That is, theinorganic color pigment and an organic compound (an organic flocculant,an organic coagulant, or the like composed of a polymer compound, suchas a cationic polymer, an anionic polymer, and a nonionic polymer) areadded to a solvent such as water, and dispersed by a disperser or thelike to form a slurry, thereby fixing the inorganic color pigment. Bydoing so, a composite pigment, in which the inorganic color pigment isfixed by an organic compound, can be produced.

The composite pigment of the present invention produced by any ofvarious methods described above may be classified for the purpose ofremoving coarse particles. Classification may be carried out by grindingor sieving. The classification method by grinding or sieving may be thesame method as the classification method already described in the above[Embodiment of the present invention (the first invention of the presentapplication)].

When the composite pigment of the present invention is furthersurface-treated with an inorganic compound and/or organic compound forsurface treatment, it may be carried out by a publicly known method suchas a wet process or a dry process, and in this case a preferableembodiment is as described in [Embodiment of the present invention (thefirst invention of the present application)].

The composite pigment of the present invention can be used in variousapplications as a pigment having a matte effect (matting pigment). Forexample, it may be used favorably in a building wall surface coatingpigment (exterior, interior, ceiling, floor and bathtub, walls andfloors of kitchen, toilet, and the like), a building material coatingpigment, an automobile coating pigment, a furniture coating pigment, andan electric and mechanical product coating pigment. Also, this mattingpigment may be blended in various paints as an alternative of so-calledmatting agent (a component for reducing gloss to be added separatelyfrom the pigment component).

The paint composition of the present invention contains theabove-described composite pigment, and if necessary, a resin, adispersant, an additive, a solvent, and the like in addition to thecomposite pigment. Specific examples of these resin, additive, andsolvent may be exactly the same as respectively listed as the examplesof resin, additive, and solvent to be included in the paint compositionin the above [Embodiment of the present invention (the first inventionof the present application)]. A dispersant is selected according to thetype of the inorganic compound and/or organic compound used forpreparing a composite pigment. For example, when silica is used for thecomposite pigment, since silica is present on the surface of thecomposite pigment, the surface condition is slightly acidic. In thiscase, it is more preferable to use a dispersant having a certain aminevalue as the dispersant.

A composite pigment, and if necessary, the above-mentioned resin,dispersant, additive, solvent, and the like are stirred with adispersing machine, and if necessary degassed to prepare a paintcomposition of the present invention.

The pigment volume concentration (PVC) of the paint composition of thepresent invention is preferably adjusted in a range of 10% to 60%. Whenimportance is attached to reduction of the gloss of a paint film, it ismore preferable to adjust the pigment volume concentration in the lowerside of the above range, specifically in a range of 20 to 40%. Further,when importance is attached to the hiding power of a paint film, it ismore preferable to adjust the pigment volume concentration in the upperside of the above range, specifically in a range of 50 to 60%.

A paint film of the present invention is formed by applying theaforedescribed paint composition to a substrate, and curing it. That is,a paint film of the paint according to the present invention may beobtained by applying the aforedescribed paint composition on a substrateusing a brush, a wool roller, or the like, followed by drying. Examplesof a substrate include building materials (concrete, mortar, gypsum,plaster, plastic, glass, earthenware, stone, wood, and the like), anautomobile body (metallic, or plastic), furniture and electromechanicalproducts (plastic, glass, earthenware, stone-made, wooden, and thelike).

Embodiment of the Present Invention (the Fourth Invention of the PresentApplication)

The composite pigment of the present invention is one in which aninorganic color pigment containing zinc element is fixed by an inorganiccompound. In the present invention, “inorganic color pigment” refers toa pigment which contains an inorganic compound as a main component, andexhibits an achromatic color such as white or black, or a chromaticcolor such as red, yellow, or blue. As examples of various inorganiccolor pigments of white, black, red, yellow, blue and green colors,various inorganic color pigments listed as “inorganic color pigments” inthe [Embodiment of the present invention (the third invention of thepresent application)] may be included as they are.

From the viewpoint of versatility of composite pigments, it ispreferable to use a white color pigment as the inorganic color pigment,and among others use of a titanium dioxide pigment is more preferable.When a titanium dioxide pigment is used as the inorganic color pigment,any out of the anatase type, rutile type, and brookite type can be usedas the crystal form of the titanium dioxide pigment, however use of therutile type, or the anatase type is preferable. When the compositepigment is blended in a paint resin, or the like, it is more preferableto use the rutile type from the viewpoint of reducing degradation of aresin due to photocatalytic activities. In this regard, as the titaniumdioxide pigment, those produced by any of so-called sulfate process andchloride process may be used.

As for the preferable size of an inorganic color pigment constitutingthe composite pigment of the present invention, the average primaryparticle diameter of 0.1 to 1.0 μm is preferable, 0.15 to 0.7 μm is morepreferable. and 0.2 to 0.5 μm is further preferable. In a case where theaverage primary particle diameter of the inorganic color pigment iswithin the above range, when the inorganic color pigment is fixed by aninorganic compound to form a composite pigment, the same can have anappropriate size (preferable particle size distribution).

The average primary particle diameter can be measured by the same methodbased on the electron microscopic method used for measuring the averageprimary particle diameter as described in the above [Embodiment of thepresent invention (the first invention of the present application)], andthe like.

There is no particular restriction on the shape of the inorganic colorpigment, and it may be any of a spherical shape, a substantiallyspherical shape, a columnar shape, a needle shape, a spindle shape, anelliptical shape, a cubic shape, a rectangular solid shape, and anindefinite shape.

The composite pigment of the present invention may contain an extenderpigment besides the above-mentioned inorganic color pigment. That is,the composite pigment of the present invention can be one obtained byfixing an inorganic color pigment containing zinc element and theextender pigment using an inorganic compound. In the present invention,an “extender pigment” is generally added as an extender in a vehicle andused for improving the flowability, the strength, or the opticalproperties, nevertheless its own refractive index, hiding power, andtinting strength are low. Examples of the extender pigment includecalcium carbonate (such as light calcium carbonate, heavy calciumcarbonate, and precipitated (synthetic) calcium carbonate), bariumsulfate (such as precipitated (synthetic) barium sulfate), aluminumhydroxide, barium carbonate, a barite powder, kaolin, talc, clay, andwhite carbon.

The size of the extender pigment is preferably substantially the same asthe inorganic color pigment. Specifically, the average primary particlediameter thereof is preferably 0.1 to 1.0 μm, more preferably 0.1 to 0.5μm, and further preferably 0.1 to 0.35 μm.

By being contained an extender pigment to a composite pigment (in otherwords, by replacing a part of the inorganic color pigment in a compositepigment with an extender pigment), it becomes possible to reduce thematerial cost of the composite pigment while maintaining an appropriatesize (preferable particle size distribution) of the composite pigment.

In a case where an extender pigment is contained in the compositepigment of the present invention, the content ratio of the inorganiccolor pigment to the extender pigment may be set appropriately.Specifically, putting the volume of the inorganic color pigment as 1,the relative volume of the extender pigment is preferably in a range of0.1 to 2, and more preferably in a range of 0.5 to 1.

Examples of an inorganic compound used for fixing the inorganic colorpigment of the present invention (and an extender pigment) include thoselisted as examples of an inorganic compound to be used for fixing anextender pigment in the above [Embodiment of the present invention (thefirst invention of the present application)] as they are. Among them, aninorganic silicon compound is preferable, and examples thereof mayinclude oxides, hydroxides, hydrous oxides, and the like of silicon. Asthe inorganic silicon compound, silica is particularly preferable. Byusing the inorganic silicon compound, the specific surface area and theoil absorption amount of the composite pigment can be adjusted toappropriate values, so that a paint containing the same can be easilyhandled.

In the composite pigment of the present invention, the content ratio ofthe inorganic color pigment (and the extender pigment) to the inorganiccompound is preferably as follows. That is, putting the volume of theinorganic color pigment (and extender pigment) as 1, the relative volumeof the inorganic compound is preferably 0.3 to 2, more preferably 0.4 to1.5, and further preferably 0.5 to 1.

The composite pigment of the present invention has a form, in which theinorganic color pigment (and the extender pigment) forms an aggregatefixed by the inorganic compound. At this time, it may be in a state inwhich there is substantially no gaps among the particles of theinorganic color pigment (and the extender pigment) (densely compositestate), or it may be in a state in which there are appropriate gaps(coarsely composite state). In addition, a plurality of aggregates inthe above-described densely composite state (primary aggregates) may begathered to form a secondary aggregate in which appropriate gaps areformed among the primary aggregates. The composite pigment may have anyshape, such as a spherical shape, a substantially spherical shape, acolumnar shape, a needle shape, a spindle shape, an elliptical shape, acubic shape, a rectangular solid shape, and an indefinite shape, howeverthe spherical shape, the substantially spherical shape, or the like ismore preferable.

In the composite pigment of the present invention, an inorganic compoundis required at least to be present among the particles of the inorganiccolor pigment (and the extender pigment) in order to express itsfunction (fixation of the pigment components), and additionally it maybe so present as to cover part or all of the surfaces of the compositepigment.

The composite pigment of the present invention contains zinc element inthe inorganic color pigment. The expression of “containing zinc elementin the inorganic color pigment” means a state in which zinc element ispresent on the particle surface of the inorganic color pigment and/or astate in which zinc element is contained (as a dope) inside theinorganic color pigment. This also applies to the case where theinorganic color pigment is zinc oxide, which means that zinc elementhaving an origin different from the matrix exists in the surface and/orthe inside of the particle of zinc oxide as a matrix.

When zinc element is contained in the composite pigment, the compositepigment can have an appropriate size (preferable particle sizedistribution). Further, it is possible to reduce the amount of smallgranules contained in the composite pigment. Since relatively largeparticles generally contribute to development of a matte effect, theabundance ratio of relatively large particles can be increased byreduction of small granules, and consequently the matte effect can beenhanced. The content of zinc element is preferably 0.5 to 5% by mass interms of Zn based on the inorganic color pigment.

A zinc element may be present on the surface of the particle of theextender pigment or may be present in a state of being contained (as adope) inside the extender pigment. Alternatively, it may be present inthe gaps among the particles of a pigment component (inorganic colorpigment and extender pigment), or in the inorganic compound for fixingthe pigment component particles each other.

Since zinc element is present at least on the particle surface of theinorganic color pigment, the composite pigment can be made to have amore appropriate size (more preferable particle size distribution), whenthe inorganic color pigment (and the extender pigment) is fixed by theinorganic compound, which is preferable. Although the reason is not veryclear, it is presumed that aggregation of the component advancesfavorably, because zinc element (zinc compound) having a relatively highaffinity for the inorganic compound is present near the surface of theinorganic color pigment (and the extender pigment).

The zinc element may be present in the inorganic color pigment invarious states, however it is preferably present in the form of zincoxide and/or zinc hydroxide. Zinc oxide and zinc hydroxide can be easilycontained in the inorganic color pigment by a treatment such asprecipitation or calcination which will be described later, with whichthe composite pigment can favorably have a more appropriate size (morepreferable particle size distribution).

With respect to the composite pigment of the present invention, theabundance ratio of the composite pigment having a particle diameter of 2μm or more in the volume cumulative distribution measured by a laserdiffraction/scattering-type particle size distribution measuringapparatus is preferably 70% or more of the total, and more preferably80% or more of the total. For measurement of the volume particle sizedistribution of the composite pigment, for example, a laserdiffraction/scattering-type particle size distribution measuringapparatus “LA-910” (manufactured by HORIBA, Ltd.) can be used.

A paint film containing the composite pigment with such a particle sizedistribution can achieve a matte effect at a high level. Specifically,the specular gloss under a geometric condition of 60° measured for apaint film having a pigment volume concentration (PVC) of 40% can bemade to 5% or less, and further the specular gloss under a geometriccondition of 85° can be reduced to 10% or less.

In the composite pigment of the present invention, it is preferable thatthe diameter on cumulative 90% (D90) in the volume cumulativedistribution measured by a laser diffraction/scattering-type particlesize distribution measuring apparatus is 30 μm or less. If so, thesufficiently smooth tactile feeling of the paint film may be realized inthe paint film containing the composite pigment, while developing amatte effect at a high level. From the viewpoint of the tactile feelingof the paint film, the diameter on cumulative 90% (D90) is morepreferably 20 μm or less.

As the evaluation index of the tactile feeling of a paint film, forexample, a friction coefficient of the paint film can be used, and asthe friction coefficient MIU (mean friction coefficient), MMD (meanfriction coefficient variation), and the like may be used. Thesefriction coefficients can be measured using, for example, a frictiontester (KES-SE manufactured by Kato Tech Co., Ltd.).

With respect to the composite pigment of the present invention, byadjusting the diameter on cumulative 90% (D90) to 20 μm or less, thevalue of MMD (mean friction coefficient variation) can be reduced to0.02 or less.

The oil absorption measured by the method described in JIS K 5101-13-1of the composite pigment of the present invention is preferably 80(mL/100 g) or less. In such a case, it is possible to sufficientlyreduce the increase in viscosity when the composite pigment of thepresent invention is blended in the paint.

The composite pigment of the present invention may further have anotherkind of an inorganic compound and/or organic compound for surfacetreatment for covering the surface in its outer surface in addition tothe above composition. This inorganic compound and/or organic compoundare present on the surface of the composite pigment of the presentinvention (more specifically, present so as to cover part or all of thesurfaces thereof), and used for so-called “surface treatment ofcomposite pigment”, therefore the function is different from that of aninorganic compound or an organic compound used for fixation as describedabove (also referred to as an “inorganic compound and/or organiccompound for fixation”). Consequently, here, the “inorganic compoundand/or organic compound for surface treatment” and the “inorganiccompound and/or organic compound for fixation” are appropriatelydistinguished from each other.

In this regard, when there is no notation such as “for fixation” or “forsurface treatment”, and it cannot be judged from the context, it isnormally regarded as “for fixation”.

Examples of such an inorganic compound for surface treatment includeoxides, hydroxides, and hydrous oxides of silicon, aluminum, zirconium,antimony, tin, cerium, zinc, and titanium. More specifically, silica,aluminum oxide, aluminum hydroxide, zirconium oxide, antimony oxide, tinoxide, cerium oxide, zinc oxide, titanium oxide, and the like can beused. By treating the composite pigment with any of these inorganiccompounds, it is possible to improve the acid resistance and theweatherability, or the dispersibility in a dispersion medium such as aresin or the like.

Examples of an organic compound for surface treatment to be present onthe surface of the composite pigment of the present invention include anorganosilicon compound such as a silicone resin, a siloxane, a silanecoupling agent, a carboxylic acid, such as stearic acid, and lauricacid, including the salts thereof, a polyol, and an amine. By treatingthe composite pigment with any of these organic compounds, it ispossible to improve the dispersibility of a resin or the like in adispersion medium.

The composite pigment of the present invention can be produced, forexample, by the following method. First, an inorganic color pigmentcontaining zinc element is prepared.

In this regard, “containing zinc element” includes not only a state inwhich zinc element exists in the particle surface of an inorganic colorpigment but also a state in which zinc element is present inside theparticle of an inorganic color pigment.

For example, a zinc compound is precipitated on the surface of aninorganic color pigment by adjusting the pH of a slurry containing theinorganic color pigment and a zinc compound source. As the zinc compoundsource, one capable of precipitating a desired zinc compound by pHadjustment can be used. For example, by using zinc sulfate heptahydrate,zinc chloride, or the like as the zinc compound source, and adjustingthe pH of the slurry to about 8 to 8.5, an oxide and/or a hydroxide ofzinc can be precipitated on the surface of the inorganic color pigment.At this time, an alkali such as sodium hydroxide can be used for pHadjustment.

Also, an inorganic color pigment having zinc element on the surface ofthe particle or inside the particle may be prepared by mixing aninorganic color pigment and a zinc compound, and heating (calcination)this mixture. The addition amount of the zinc compound and thetemperature of heating (calcination) may be appropriately set accordingto the kind of the inorganic color pigment and the like.

Further, when a titanium dioxide pigment is used as an inorganic colorpigment, a titanium dioxide pigment having a zinc compound on theparticle surface may be also prepared as follows. That is, a hydrate oftitanium dioxide, and a zinc compound as an additive for calcination aremixed and calcined. The amount of the zinc compound is preferably 0.1 to2.0% by mass in terms of ZnO with respect to titanium dioxide. Althoughthe calcination conditions can be set appropriately, the calcinationtemperature is preferably 800 to 1000° C. As the additive forcalcination, various zinc compounds may be used, but it is preferable touse an oxide and/or hydroxide of zinc.

Subsequently, the inorganic color pigment obtained as above and, ifnecessary, an extender pigment, furthermore, an inorganic compoundsource are added into a solvent such as water, and dispersed by adispersing machine such as a disperser to form a slurry.

The “inorganic compound source” means herein a material whichprecipitates an inorganic compound by adjusting the pH of a slurry asdescribed later. Sodium silicate is preferable as the inorganic compoundsource. As sodium silicate, any of No. 1, No. 2 and No. 3 defined in JIS1408-1966 can be used, but use of No. 3 is more preferable from theviewpoint of availability and handling.

In preparing the slurry, the volume ratio (Va/Vb) of the volume (Va) ofthe inorganic compound source to the volume (Vb) of the inorganic colorpigment (and the extender pigment) is preferably set in a range of 0.3to 2. In this case, the volume (Va) of the inorganic compound sourcemeans the volume in terms of an inorganic compound to be precipitated asa result of the pH adjustment described later. By adjusting to such avolume ratio, a sufficient fixation effect by the inorganic compound canbe obtained, so that the composite pigment can acquire an appropriatesize (preferable particle size distribution).

Subsequently, by adjusting the pH of the slurry, an inorganic compoundderived from the inorganic compound source is precipitated, and theinorganic color pigment (and the extender pigment) is fixed by theinorganic compound.

As an inorganic compound source, a compound which becomes the aboveinorganic compound by precipitation can be used, and the pH forprecipitation can be appropriately set according to the inorganiccompound. For example, when sodium silicate is used, it is preferable toadjust the pH to 2 to 10 by adding dilute sulfuric acid. By doing so, itis possible to yield a composite pigment having an appropriate size(preferable particle size distribution) while reducing the formation offree silica. In the pH adjustment by adding dilute sulfuric acid, it ismore preferable to adjust the pH in a range of 6 to 9, and furtherpreferably in a range of 7 to 8. Further, it is preferable toprecipitate an inorganic compound while heating the slurry and keepingthe temperature in a range of about 50 to 100° C.

Following the above step, if necessary, washing, dehydration, and dryingmay be carried out by publicly known methods, and grinding may beperformed appropriately. Further, if necessary, the above dried productmay be calcined at a higher temperature. The calcination temperature maybe appropriately set, and, for example, about 300 to 900° C. ispreferable.

In the above, the method of fixing the inorganic color pigment (and theextender pigment) by the inorganic compound has been described, howeverit is also possible to fix the inorganic color pigment (and the extenderpigment) by an organic compound. That is, an extender pigment and anorganic compound (an organic flocculant, an organic coagulant, or thelike composed of a polymer compound, such as a cationic polymer, ananionic polymer, and a nonionic polymer) are added to a solvent such aswater, and dispersed by a dispersing machine such as a disperser to forma slurry, thereby fixing the inorganic color pigment (and the extenderpigment). By doing so, a composite pigment, in which the inorganic colorpigment (and the extender pigment) is fixed by an organic compound, canbe produced.

The composite pigment of the present invention produced by any ofvarious methods described above may be classified for the purpose ofremoving coarse particles. Classification may be carried out by grindingor sieving. The classification method by grinding or sieving may be thesame method as the classification method already described in the above[Embodiment of the present invention (the first invention of the presentapplication)].

When the composite pigment of the present invention is furthersurface-treated with an inorganic compound and/or organic compound forsurface treatment, it may be carried out by a publicly known method suchas a wet process or a dry process, and in this case a preferableembodiment is as described in [Embodiment of the present invention (thefirst invention of the present application)].

The composite pigment of the present invention can be used in variousapplications as a matting pigment. For example, it may be used favorablyas a matting pigment to be blended in a paint composition for coatingbuilding wall surface (exterior, interior, ceiling, floor and bathtub,walls and floors of kitchen, toilet, and the like), for coating buildingmaterials, for coating vehicles, for coating furniture, and for coatingelectromechanical products.

The composite pigment of the present invention may be blended in variouspaints as so-called matting agent (a component for developing a matteeffect to be added into a paint separately from the color material).

The paint composition of the present invention contains the compositepigment and/or the matting pigment, a resin, and, if necessary, also anadditive, a solvent, a dispersant, or the like.

As a resin contained in the paint composition of the present invention,those listed as the examples of the resins to be contained in a paintcomposition in the above [Embodiment of the present invention (the firstinvention of the present application)] may be used.

Examples of an additive contained in the paint composition of thepresent invention include various kinds of commonly used emulsifiers,antifreezing agents, pH adjusters, thickeners, and defoaming agents.Specific examples of the solvent include those listed as the examples ofthe solvent to be used in the paint composition in the above [Embodimentof the present invention (the first invention of the presentapplication)] as they are.

A dispersant is appropriately selected corresponding to the type of aninorganic compound used for synthesizing a composite pigment. Forexample, when silica is used as the inorganic compound, since silica ispresent at the surface of the composite pigment, the surface is slightlyacidic. In this case, it is more preferable to use a dispersant having acertain amine value as the dispersant. Specific examples thereof includethose listed as the examples of the dispersant having an amine value inthe above [Embodiment of the present invention (the first invention ofthe present application)] as they are.

The composite pigment of the present invention itself also functions asa color material. Therefore, when the paint composition of the presentinvention is prepared, it is not necessary to separately add a colormaterial, but it is also possible to add a color material separatelythereto in addition to the composite pigment. As the color material,common pigments, dyes, and the like may be used. As a pigment to becontained in the paint composition of the present invention, thoselisted as examples of the pigment which can be used as a “colormaterial” in the paint composition in the above [Embodiment of thepresent invention (the first invention of the present application)] maybe used as they are.

The composite pigment and the resin, and if necessary theabove-mentioned dispersant, additive, solvent, color material, and thelike are stirred with a dispersing machine, and if necessary degassingis performed, to prepare a paint composition of the present invention.

The pigment volume concentration (PVC) of the paint composition of thepresent invention is preferably adjusted in a range of 10% to 60%. Whenimportance is attached to reduction of the gloss of a paint film, it ismore preferable to adjust the pigment volume concentration in the lowerside of the above range, namely in a range of 20 to 40%. Further, whenimportance is attached to the hiding power of a paint film, it is morepreferable to adjust the pigment volume concentration in the upper sideof the above range, namely in a range of 50 to 60%.

A paint film of the present invention is formed by coating theaforedescribed paint composition onto an object and curing it. That is,a paint film of the present invention may be obtained by coating theaforedescribed paint composition onto an object using a brush, a woolroller, or the like, followed by drying. Examples of an object includebuilding materials (concrete, mortar, gypsum, plaster, plastic, glass,earthenware, stone, wood, and the like), a vehicle main body (metallic,or plastic), furniture and electromechanical products (plastic, glass,earthenware, stone-made, wooden, and the like).

Embodiment of the Present Invention (the Fifth Invention of the PresentApplication)

A composite pigment of the present invention contains extender pigmentparticles fixed by an inorganic compound and/or organic compound, inother words it is a particulate aggregate having gathered a plurality of(two or more) extender pigment (specifically, particles of the extenderpigment) by means of an inorganic compound and/or organic compound.

In this regard, the content of the descriptions in the above [Embodimentof the present invention (the first invention of the presentapplication)] through [Embodiment of the present invention (the fourthinvention of the present application)] shall apply as they are in thecurrent Embodiment of the present invention, unless otherwise specified.

In the present invention, an “extender pigment” means a pigment, whichis generally added as an extender in a vehicle and used for improvingthe flowability, the strength, or the optical properties, although itsown refractive index, hiding power, and tinting strength are low, andwhich becomes transparent or translucent when it is kneaded with avehicle. Examples of the extender pigment include barium sulfate (suchas precipitated (synthetic) barium sulfate), calcium carbonate (such aslight calcium carbonate, heavy calcium carbonate, and precipitated(synthetic) calcium carbonate), aluminum hydroxide, barium carbonate, abarite powder, kaolin, talc, clay, and white carbon. As the extenderpigment, calcium carbonate, and barium sulfate are preferable. Inparticular, when barium sulfate is used as an extender pigment, acidresistance, alkali resistance, heat resistance, radiation shieldingperformance, and the like can be imparted to a composite pigment.

The size of the extender pigment particles constituting the compositepigment of the present invention is preferably 0.1 μm or more and 1.0 μmor less in terms of the average primary particle diameter, morepreferably 0.15 μm or more and 0.7 μm or less, and more preferably 0.2μm or more and 0.5 μm or less. In a case in which the average primaryparticle diameter of an extender pigment is within the above range, whenthe extender pigment particles are gathered and fixed by an inorganiccompound, the composite pigment can have an appropriate size (apreferable particle size distribution).

The average primary particle diameter can be measured by an electronmicroscopic method. More particularly, the particles of an extenderpigment are photographed using a transmission electron microscope(H-7000 manufactured by Hitachi, Ltd.), an image processing is performedusing an automatic image processing and analyzing apparatus (LUZEX APmanufactured by NIRECO CORPORATION), and the primary particle diameteris measured for 2,000 particles, and the average value thereof isregarded as the average primary particle diameter.

There is no particular restriction on the particle shape of an extenderpigment, and it may be any of various shapes, such as a spherical shape,a substantially spherical shape, a columnar shape, a needle shape, aspindle shape, an elliptical, a cubic shape, a rectangular solid shape,and an indefinite shape.

Examples of an inorganic compound used for fixing the extender pigmentparticles include an inorganic compound having a fixing property or anaggregating property, such as oxides, hydroxides, and hydrous oxides ofsilicon, aluminum, zirconium, antimony, tin, cerium, zinc, and titanium.More specific examples thereof include silica, aluminum oxide, aluminumhydroxide, zirconium oxide, antimony oxide, tin oxide, cerium oxide,zinc oxide, and titanium oxide; and at least one selected from inorganiccompounds other than an extender pigment may be used.

As the inorganic compound, an inorganic silicon compound is preferable,and examples thereof include oxides, hydroxides, and hydrous oxides ofsilicon. As the inorganic silicon compound, silica is particularlypreferable. By using an inorganic silicon compound, the specific surfacearea and the oil absorption amount of a composite pigment can beappropriate values, and a paint blending the same can be easily handled.

In the composite pigment of the present invention, with respect to thecontent ratio between the extender pigment particles and the inorganiccompound in the composite pigment, putting the volume of the extenderpigment as 1, the relative volume of the inorganic compound ispreferably 0.1 or more and 3 or less. From the viewpoint of reducing thegloss of a paint film, the relative volume of the inorganic compound ismore preferably 0.3 or more and 3 or less with respect to 1 volume ofthe extender pigment. Furthermore, from the viewpoint of the viscosityof the paint (handling), the relative volume of the inorganic compoundis further preferably 0.1 or more and 1.5 or less with respect to 1volume of the extender pigment particles. In addition, from both theviewpoints of a gloss reduction of the paint film and handling of thepaint, the relative volume of the inorganic compound is still furtherpreferably 0.3 or more and 1.5 or less with respect to 1 volume of theextender pigment particles.

For fixing the extender pigment particles, an organic compound having aproperty similar to that of the above inorganic compound (the propertyto fix the extender pigment particles) may be used together with theabove inorganic compound, or separately. As the organic compound, anorganic flocculant, an organic coagulant, or the like may be used. Thereis no particular restriction on the organic flocculant, and the organiccoagulant, insofar as they are capable of catching and aggregating aplurality of particles with their polymer chains, and a polymer compoundsuch as a cationic polymer, an anionic polymer, and a nonionic polymermay be used. The content of the organic compound may be appropriatelyset, and putting the mass of the extender pigment component as 1, therelative mass of the organic compound is preferably 0.001 or more and 1or less, more preferably 0.001 or more and 0.1 or less, and furtherpreferably 0.01 or more and 0.05 or less.

The composite pigment of the present invention has a form, in which theextender pigment particles form an aggregate fixed by the inorganiccompound and/or organic compound. At this time, it may be in a state inwhich there is substantially no gaps among the extender pigmentparticles (densely composite state), or it may be in a state in whichthere are appropriate gaps (coarsely composite state). In addition, aplurality of aggregates in the above-described densely composite state(primary aggregates) may be gathered to form a secondary aggregate inwhich appropriate gaps are formed among the primary aggregates. Thecomposite pigment particle may have any shape, such as a sphericalshape, a substantially spherical shape, a columnar shape, a needleshape, a spindle shape, an elliptical shape, a cubic shape, arectangular solid shape, and an indefinite shape, however the sphericalshape, the substantially spherical shape, or the like is morepreferable.

In the composite pigment of the present invention, the inorganiccompound and/or organic compound is required at least to be presentamong the particles of the extender pigment in order to exert itsfunction (function to fix the extender pigment particles each other),and further the inorganic compound and/or organic compound may be sopresent as to cover part or all of the particle surfaces of thecomposite pigment.

The diameter on cumulative 50% (D50) in the volume cumulativedistribution measured by a laser diffraction/scattering-type particlesize distribution measuring apparatus of the composite pigment of thepresent invention is preferably 1 μm or more and 15 μm or less. Formeasurement of the volume particle size distribution of the compositepigment, for example, a laser diffraction/scattering-type particle sizedistribution measuring apparatus “LA-910” (manufactured by HORIBA, Ltd.)may be used.

When D50 takes such a value, the matte effect can be expressed at a highlevel in a paint film containing the composite pigment. Specifically, ina case where a clear paint is prepared at a pigment volume concentration(PVC) of 20%, and this is coated to form a paint film, which speculargloss is measured according to JIS K 5600-4-7: 1999, the specular glossunder a geometric condition of 60° can be reduced to 5% or less. Thismeans that the gloss is reduced even to the degree of a gloss reductionreferred to as “matting” over the degree of a gloss reduction generallyreferred to as “70% gloss (specular gloss of 55 to 65% at 60°)”, “50%gloss” or “30% gloss”.

The composite pigment of the present invention preferably has a diameteron cumulative 90% (D90) in the volume cumulative distribution measuredby a laser diffraction/scattering-type particle size distributionmeasuring apparatus of 5 μm or more and 30 μm or less. By doing so, itbecomes possible to sufficiently reduce so-called “85° gloss” in thepaint film containing the composite pigment. Specifically, in a casewhere a clear paint is prepared at a pigment volume concentration (PVC)of 20%, and this is coated to form a paint film, the specular glossmeasured under a geometric condition of 85° according to JIS K 5600-4-7:1999 can be reduced to 10% or less.

In addition, when the composite pigment of the present invention isblended in a paint film, the paint film gives a good (smooth) tactilefeeling, and the diameter on cumulative 90% (D90) is preferably 30 μm orless because the sufficiently smooth tactile feeling of the paint filmcan be attained. From the viewpoint of the tactile feeling of the paintfilm, the diameter on cumulative 90% (D90) is more preferably 20 μm orless.

As the evaluation index of the tactile feeling of a paint film, forexample, the friction coefficient of a paint film can be used, and asthe friction coefficient, MIU (mean friction coefficient), MMD (meanfriction coefficient variation), or the like may be used. These frictioncoefficients may be measured using, for example, with a friction tester(KES-SE manufactured by Kato Tech Co., Ltd.).

In the case of the composite pigment of the present invention, when thediameter on cumulative 90% (D90) is made 20 μm or less, the value of MMD(mean friction coefficient variation) can be lowered to 0.02 or less, orin a favorable case to 0.01 or less.

The oil absorption of the composite pigment of the present inventionmeasured by the method described in JIS K 5101-13-1 is preferably 80(mL/100 g) or less. In such a case, it is possible to sufficientlyreduce the increase in viscosity when the composite pigment of thepresent invention is blended in a paint. From the viewpoint of reductionof the viscosity of a paint (improvement of handling), the oilabsorption amount is more preferably 60 (mL/100 g) or less.

Next, the composite pigment of the present invention also containsinorganic color pigment particles in addition to the extender pigmentparticles, more particularly it includes the inorganic color pigmentparticles and the extender pigment particles, both of which are fixed bythe inorganic compound and/or organic compound. In other words, in thecomposite pigment in which the extender pigment particles are fixed bythe inorganic compound and/or organic substance, which is one embodimentof the present invention described above, part of the extender pigmentparticles are replaced with inorganic color pigment particles.Therefore, the composite pigment of the present invention is a compositepigment in which at least the inorganic color pigment particles and theextender pigment particles are fixed by the inorganic compound and/ororganic compound.

In the present invention, the term “inorganic color pigment particle”refers to a pigment which contains an inorganic compound as a maincomponent and exhibits an achromatic color such as white or black, or achromatic color such as red, yellow, or blue. Examples of a whiteinorganic color pigment include titanium dioxide, zinc oxide, and basiclead carbonate. Examples of a black inorganic color pigment include alower titanium oxide, titanium oxynitride (titanium black), carbonblack, bone black (bone charcoal), graphite, iron black, cobalt chromateblack spinel, iron chromate composite oxide, copper chromate spinelblack composite oxide, and Fe—Mn—Bi black. Examples of a red inorganiccolor pigment include red iron oxide, and molybdenum red. Examples of ayellow inorganic color pigment include nickel antimony titanium yellow,chrome antimony titanium buff, synthetic iron oxide yellow, and chromeyellow. Examples of a blue inorganic color pigment include ultramarineblue, iron blue, and cobalt blue. Examples of a green inorganic colorpigment include cobalt green, chrome green, chromium oxide green, cobaltchromate green spinel, and cobalt titanate green spinel. At least onekind selected from these inorganic color pigments may be used.

From the viewpoint of versatility of composite pigments, it ispreferable to use a white color pigment as the inorganic color pigment,and among others use of a titanium dioxide pigment is more preferable.When a titanium dioxide pigment is used as the inorganic color pigment,any out of the anatase type, rutile type, and brookite type can be usedas the crystal form of the titanium dioxide pigment, however use of therutile type, or the anatase type is preferable. When the compositepigment is blended in a paint resin, or the like, it is more preferableto use the rutile type from the viewpoint of reducing degradation of aresin due to photocatalytic activities. In this regard, as the titaniumdioxide pigment, those produced by any of so-called sulfate process andchloride process may be used.

The size of an inorganic color pigment particle constituting thecomposite pigment of the present invention in terms of the averageprimary particle diameter is preferably 0.1 μm or more and 1.0 μm orless, more preferably 0.15 μm or more and 0.7 μm or less, and furtherpreferably 0.2 μm or more and 0.5 μm or less. In a case where theaverage primary particle diameter of the inorganic color pigment iswithin the above range, when the extender pigment particle and theinorganic color pigment particles are fixed by an inorganic compound toform a composite pigment, the same can have an appropriate size(preferable particle size distribution).

When the inorganic color pigment constituting the composite pigment ofthe present invention is a titanium oxide pigment, the average primaryparticle diameter thereof is preferably 0.1 μm or more and 1.0 μm orless, more preferably 0.1 μm or more and 0.5 μm or less, and furtherpreferably 0.1 μm or more and 0.3 μm or less. By adjusting the averageprimary particle diameter of the titanium oxide pigment within the aboverange, when the titanium oxide pigment and the extender pigment areformed into a composite pigment, the size thereof can be appropriate. Asa result, the low-gloss property (matte effect) and the hiding power canbe improved, and further the tactile feeling of the paint film can bemade smoother, which is preferable. The average primary particlediameter can be measured by the above-mentioned electron microscopicmethod.

There is no particular restriction on the particle shape of theinorganic color pigment, and it may be any of a spherical shape, asubstantially spherical shape, a columnar shape, a needle shape, aspindle shape, an elliptical shape, a cubic shape, a rectangular solidshape, and an indefinite shape.

In the composite pigment of the present invention, the extender pigmentparticles enter between the inorganic color pigment particles andfunction as a spacer to provide appropriate gaps between the particles.In order to exert such a function, the volume of the extender pigmentparticle is important. In this respect, calcium carbonate has arelatively small specific gravity, and can secure a sufficient volumeeven with a small amount used. Therefore, from the viewpoint of cost, itis more preferable to use calcium carbonate as the extender pigment.Among various types of calcium carbonate, precipitated (synthetic)calcium carbonate is particularly preferable. This is becauseprecipitated (synthetic) calcium carbonate can be easily designed tohave a desired particle size, and therefore one with a desired particlesize is easily available.

The extender pigment particle constituting the composite pigment of thepresent invention is preferably substantially the same as the inorganiccolor pigment particle in size. Specifically, the average primaryparticle diameter thereof is preferably 0.1 μm or more and 1.0 μm orless, more preferably 0.1 μm or more and 0.5 μm or less, and furtherpreferably 0.1 μm or more and 0.35 μm or less. In a case where theaverage primary particle diameter of the extender pigment is within theabove range, when the inorganic color pigment and the extender pigmentare made to form a composite, the composite pigment can have anappropriate size, so that the low-gloss property (matte effect) and thehiding power can be improved, and also the tactile feeling of the paintfilm can be made smoother, which is preferable.

In the composite pigment of the present invention, the content ratio ofthe inorganic color pigment particle to the extender pigment particlemay be set appropriately. Specifically, putting the volume of theinorganic color pigment particle as 1, the relative volume of theextender pigment particle is preferably in a range of 0.1 or more and 2or less, and more preferably in a range of 0.5 or more and 1 or less.

Further, in a case where the inorganic color pigment is a titanium oxidepigment in the composite pigment of the present invention, although thecontents of the titanium oxide pigment and the extender pigment can beappropriately set, if the mass of titanium oxide is put as 1, therelative mass of the extender pigment is preferably 0.01 or more and 100or less, more preferably 0.1 or more and 10 or less, and furtherpreferably 0.2 or more, and 1 or less.

For very firmly fixing the particles of the above inorganic colorpigment (such as titanium oxide pigment) and the particles of theextender pigment, the above inorganic compound and/or organic compoundis used.

When an inorganic compound is used for the composite pigment of thepresent invention, the content ratio of the inorganic compound to theinorganic color pigment particles and the extender pigment particles ispreferably as follows. That is, putting the volume of the inorganiccolor pigment particles and the extender pigment particles as 1, thevolume of the inorganic compound is preferably 0.3 or more and 2 orless, more preferably 0.4 or more and 1.5 or less, and furtherpreferably 0.5 or more and 1 or less.

As an organic compound to constitute a composite pigment of the presentinvention, an organic flocculant, an organic coagulant, and the like maybe used. There is no particular restriction on the organic flocculant,and the organic coagulant, insofar as they are capable of catching andaggregating a plurality of particles with their polymer chains, and apolymer compound such as a cationic polymers, an anionic polymer, and anonionic polymer may be used. The content relative to the organiccompound may be appropriately set, however putting the mass of thepigment component as 1, the relative mass of the organic compound ispreferably 0.001 or more and 1 or less, more preferably 0.001 or moreand 0.1 or less, and further preferably 0.01 or more and 0.05 or less.

The composite pigment of the present invention takes the form of anaggregate in which at least the particles of the inorganic color pigment(titanium oxide pigment, or the like) and the particles of the extenderpigment are fixed by an inorganic compound and/or organic compound.Although there can be various modes of composite pigment, a typicalexample is a mode in which at least a plurality of the inorganic colorpigment particles, and a plurality of the extender pigment particles arefixed by an inorganic compound and/or an organic compound. In otherwords, in the one embodiment described above of the present inventionwith respect to the composite pigment comprising the inorganic colorpigment particles and the extender pigment particles, there can be amode in which the respective numbers of the inorganic color pigmentparticles and the extender pigment particles fixed therein are plural(two or more).

In this case, a state in which an extender pigment particle is presentamong the inorganic color pigment particles is preferable, rather than astate in which the same kind particles (group of inorganic color pigmentparticles each other, or group of extender pigment particles each other)gather at a specific position. Since the extender pigment particles playthe role of a spacer, the low-gloss property (matte effect) and thehiding power can be improved. Naturally, it is not always necessary thatthe extender pigment particles exist between all the inorganic colorpigment particles, and the same kind of constituent particles may gatherto form its own region in part of the regions of the composite pigment.However, a mode in which, when the composite pigment is viewedmacroscopically, a plurality of the inorganic color pigment particlesand the extender pigment particles are distributed evenly, ispreferable.

For the sake of dispersing a plurality of the inorganic color pigmentparticles and the extender pigment particles in the composite pigment,the particle shape of the inorganic color pigment and the extenderpigment should preferably be spherical or substantially spherical.

In this regard, for the sake of achieving a state in which a pluralityof the inorganic color pigment particles (titanium oxide pigment, or thelike) and the extender pigment particles in the composite pigment aredistributed evenly, the average primary particle diameter of theextender pigment is preferably nearly equal to the average primaryparticle diameter of the inorganic color pigment, or smaller than theaverage primary particle diameter of the inorganic color pigment asdescribed above. Specifically, putting the average primary particlediameter of the inorganic color pigment as 1, the average primaryparticle diameter of the extender pigment is preferably 0.1 or more and1.5 or less, and more preferably 0.5 or more and 1 or less. This isbecause the extender pigment particles can function more easily asspacers among the inorganic color pigment particles, by using extenderpigment particles having a size nearly equal to the inorganic colorpigment particles, or smaller than the inorganic color pigmentparticles.

The inorganic color pigment particles (titanium oxide pigment, or thelike) and the extender pigment particle may be in a state where there isalmost no gap between them (densely composite state) by means of aninorganic compound and/or organic compound, or in a state where thereare appropriate gaps (coarsely composite state). In addition, aplurality of aggregates in the above-described densely composite state(primary aggregates) may be gathered to form a secondary aggregate inwhich appropriate gaps are formed among the primary aggregates. Thecomposite pigment may have any shape, such as a spherical shape, asubstantially spherical shape, a columnar shape, a needle shape, aspindle shape, an elliptical shape, a cubic shape, a rectangular solidshape, and an indefinite shape, however the spherical shape, thesubstantially spherical shape, or the like is more preferable.

In the composite pigment of the present invention, the inorganiccompound and/or the organic compound is required to be present at leastamong the constituent particles (inorganic color pigment particles suchas titanium oxide pigment, extender pigment particles, and the like) ofthe composite pigment, they may be also present so as to cover part orall of the surface of the composite pigment. In this case, payingattention to both the functions, the former (an inorganic compoundand/or organic compound present among the constituent particles of thecomposite pigment and used for fixing the inorganic color pigmentparticles each other) which is referred to as an “inorganic compoundand/or organic compound for fixation”, and the latter (an inorganiccompound and/or organic compound present so as to cover part or all ofthe surfaces of the composite pigment, and used for so-called “surfacetreatment of composite pigment”) is referred to as an “inorganiccompound and/or organic compound for surface treatment” aredistinguished from each other.

In this regard, when there is no specific notation such as “forfixation” or “for surface treatment”, it normally means “for fixation”.

With respect to the composite pigment containing the inorganic colorpigment particles of the present invention, it is preferable that thediameter on cumulative 90% (D90) in the volume cumulative distributionmeasured by a laser diffraction/scattering-type particle sizedistribution measuring apparatus is 30 μm or less. If so, thesufficiently smooth tactile feeling of a paint film may be realizedwhile developing a matte effect at a high level in the paint filmcontaining the composite pigment. From the viewpoint of the tactilefeeling of a paint film, the diameter on cumulative 90% (D90) is morepreferably 20 μm or less, and further preferably 10 μm or less.

The diameter on cumulative 90% (D90) of a composite pigment can bemeasured using the laser diffraction/scattering-type particle sizedistribution measuring apparatus. As the evaluation index of the tactilefeeling of a paint film, for example, the friction coefficient of thepaint film can be used, and as the friction coefficient, MIU (meanfriction coefficient), MMD (mean friction coefficient variation), or thelike may be used. In the case of the composite pigment of the presentinvention, when the diameter on cumulative 90% (D90) is made 20 μm orless, the value of MMD (mean friction coefficient variation) can belowered to 0.02 or less.

A general flat emulsion paint develops a matte effect, however thesurface of a paint film becomes rough. As a result, the paint film givesa rough tactile feel, the paint film is easily stained, and it is oftendifficult to remove the stain. In contrast, when the composite pigmentof the present invention having a diameter on cumulative 90% (D90) of 30μm or less, and preferably 20 μm or less is used, the surface of thepaint film becomes smooth so that the paint film gives a smooth tactilefeel, while a low-gloss property (matte effect) is exhibited, whichconstitutes unique design. At the same time, a functionality can beimparted such that stain is hardly attached to the paint film and thestain is easily removed.

The composite pigment containing the inorganic color pigment particlesof the present invention has preferably a median diameter D50 (diameteron cumulative 50% in the volume cumulative distribution) measured by thelaser diffraction/scattering-type particle size distribution measuringapparatus of 1 μm or more and 10 μm or less, more preferably 1 μm ormore and 6 μm or less, and further preferably 1 μm or more and 3 μm orless. When the composite pigment of the present invention is used forformation of a paint, the surface of a paint film can be made evensmoother. As a result, smoothness of the tactile feeling of a paint filmand resistance of the paint film to stain (easiness of removal of thestain) can be further improved while exhibiting the low-gloss property(matte effect).

The composite pigment containing the inorganic color pigment particlesof the present invention is preferably made to have an oil absorptionmeasured by the method described in JIS K 5101-13-1 of 80 (mL/100 g) orless. By doing so, it is possible to sufficiently reduce the increase inviscosity when the composite pigment of the present invention is blendedin a paint.

The composite pigment of the present invention may contain zinc elementin the inorganic color pigment particles. The expression of “containingzinc element in the inorganic color pigment particles” means a state inwhich zinc element is present on the particle surface of the inorganiccolor pigment and/or a state in which zinc element is contained (as adope) inside the inorganic color pigment particles. This also applies tothe case where the inorganic color pigment is zinc oxide, which meansthat zinc element having an origin different from the matrix exists inthe surface and/or the inside of the particle of zinc oxide as a matrix.

When zinc element is contained in the composite pigment particles, thecomposite pigment can have an appropriate size (preferable particle sizedistribution). Further, it is possible to reduce the amount of smallgranules contained in the composite pigment. Since relatively largeparticles generally contribute to development of a matte effect, theabundance ratio of relatively large particles can be increased byreduction of small granules, and consequently the matte effect can beenhanced. The content of zinc element is preferably 0.5% by mass or moreand 5% by mass or less in terms of Zn based on the inorganic colorpigment.

A zinc element may be present on the surface of the particle of theextender pigment or may be present in a state of being contained (as adope) inside the extender pigment particles. Alternatively, it may bepresent in the gaps among the particles of a pigment component(inorganic color pigment and extender pigment), or in the inorganiccompound for fixing the pigment component particles each other.

Since zinc element is present at least on the particle surface of theinorganic color pigment, the composite pigment can be made to have amore appropriate size (more preferable particle size distribution), whenthe inorganic color pigment particles (and the extender pigmentparticles) are fixed by the inorganic compound, which is preferable.Although the reason is not very clear, it is presumed that aggregationof the component advances favorably, because zinc element (zinccompound) having a relatively high affinity for the inorganic compoundis present near the surface of the inorganic color pigment particles(and the extender pigment particles).

The zinc element may be present in the inorganic color pigment particlesin various forms, however it is preferably present in the form of zincoxide and/or zinc hydroxide. Zinc oxide and zinc hydroxide can be easilycontained in the inorganic color pigment particles by a treatment suchas precipitation or calcination which will be described later, withwhich the composite pigment can favorably have a more appropriate size(more preferable particle size distribution).

With respect to the composite pigment containing the inorganic colorpigment particles of the present invention, the abundance ratio of thecomposite pigment having a particle diameter of 2 μm or more in thevolume cumulative distribution measured by a laserdiffraction/scattering-type particle size distribution measuringapparatus is preferably 70% or more of the total, and more preferably80% or more of the total. For measurement of the volume particle sizedistribution of the composite pigment, for example, a laserdiffraction/scattering-type particle size distribution measuringapparatus “LA-910” (manufactured by HORIBA, Ltd.) can be used.

A paint film containing the composite pigment with such a particle sizedistribution can achieve a matte effect at a high level. Specifically,the specular gloss under a geometric condition of 60° measured for apaint film having a pigment volume concentration (PVC) of 40% can bemade to 5% or less, and further the specular gloss under a geometriccondition of 85° can be reduced to 10% or less.

The composite pigment of the present invention may further contain inits outer surface an inorganic compound and/or organic compound forsurface treatment in addition to the above composition. The inorganiccompound and/or organic compound is present on the surface of thecomposite pigment of the present invention (more specifically, presentso as to cover part or all of the surfaces thereof) and used forso-called “surface treatment of composite pigment”, therefore itsfunction is different from that of an inorganic compound or an organiccompound used for fixation as described above (also referred to as an“inorganic compound and/or organic compound for fixation”).Consequently, here, the “inorganic compound and/or organic compound forsurface treatment” and the “inorganic compound and/or organic compoundfor fixation” are appropriately distinguished from each other.

In this regard, when there is no notation such as “for fixation” or “forsurface treatment”, and it cannot be judged from the context, it isnormally regarded as “for fixation”.

Examples of such an inorganic compound for surface treatment includeoxides, hydroxides, and hydrous oxides of silicon, aluminum, zirconium,antimony, tin, cerium, zinc, and titanium. More specifically, silica,aluminum oxide, aluminum hydroxide, zirconium oxide, antimony oxide, tinoxide, cerium oxide, zinc oxide, titanium oxide, and the like can beused. By treating the composite pigment with any of these inorganiccompounds, it is possible to improve the acid resistance and theweatherability, or the dispersibility in a dispersion medium such as aresin or the like.

Examples of an organic compound for surface treatment to be present onthe surface of a composite pigment of the present invention include anorganosilicon compound such as a silicone resin, a siloxane, a silanecoupling agent, a carboxylic acid such as stearic acid and lauric acid,or the salts thereof, a polyol, and an amine. By treating the compositepigment with any of these organic compounds, it is possible to improvethe dispersibility in a dispersion medium such as a resin or the like.

If necessary, the composite pigment of the present invention may containappropriately various color pigments, organic pigments, organic dyes,functional pigments such as a heat shielding pigment, or the like inaddition to the inorganic color pigment particles (such as titaniumoxide pigment), and the extender pigment particles.

The composite pigment of the present invention can be produced, forexample, by the following method. That is, the extender pigmentparticles and the inorganic compound source are added to a solvent suchas water and dispersed with a disperser or the like to form a slurry.

The “inorganic compound source” means herein a material, whichprecipitates as an inorganic compound by adjusting the pH of a slurry asdescribed later. Examples of such an inorganic compound source includesodium silicate, sodium aluminate, aluminum sulfate, zirconium sulfate,stannous chloride, and titanium tetrachloride. Sodium silicate ispreferable as an inorganic compound source. As sodium silicate, any ofNo. 1, No. 2 and No. 3 defined in JIS 1408-1966 can be used, but use ofNo. 3 is preferable from the viewpoint of availability and handling.

In preparing the slurry, the volume ratio (Va/Vb) of the volume (Va) ofthe inorganic compound source to the volume (Vb) of the extender pigmentparticles is preferably set at 0.1 or more and 3 or less. In this case,the volume (Va) of the inorganic compound source means the volume interms of an inorganic compound to be precipitated as a result of the pHadjustment described later. By adjusting to such a volume ratio, asufficient fixation effect of the inorganic compound can be obtained, sothat the composite pigment can acquire an appropriate size (preferableparticle size distribution).

Subsequently, by adjusting the pH of the slurry, an inorganic compoundderived from the inorganic compound source precipitates, and theextender pigment particles are fixed by the inorganic compound.

When sodium silicate is used as the inorganic compound source, it ispreferable to heat the slurry and keep the temperature in a range ofabout 50° C. or more and 100° C. or less, and to add dilute sulfuricacid to adjust the pH to 2 or more and 10 or less. By doing so, it ispossible to obtain a composite pigment having an appropriate size(preferable particle size distribution) while reducing the formation offree silica. In the pH adjustment by adding the dilute sulfuric acid,the pH is preferably adjusted into a range of 6 or more and 9 or less,and more preferably adjusted into a range of 7 or more and 8 or less.

When aluminum sulfate is used as an inorganic compound source, it ispreferable to heat up the slurry and adjust the pH to 4 or more and 13or less by adding sodium hydroxide while keeping the temperature atabout 50 to 100° C.

Following the above steps, if necessary, it is possible to performwashing and dehydration, drying, and appropriate grinding by a publiclyknown method. Further, if necessary, the above dried product may becalcined at a higher temperature. The calcination temperature can beappropriately set, for example, preferably at about 300° C. or more and900° C. or less.

In the above, the method of fixing the extender pigment particles by aninorganic compound has been described, however it is also possible tofix the extender pigment particles by an organic compound. That is, theextender pigment particles and an organic compound (an organicflocculant, an organic coagulant, or the like composed of a polymercompound, such as a cationic polymer, an anionic polymer, and a nonionicpolymer) are added to a solvent such as water, and dispersed with adisperser or the like to form a slurry, thereby fixing the extenderpigment particles. By doing so, a composite pigment, in which theextender pigment particles is fixed by an organic compound, can beproduced.

The composite pigment containing the inorganic color pigment particlesaccording to the present invention can be produced by various knownmethods, and also granulated, for example, with a granulator, however itis difficult to produce fine composite pigment. To cope with the above,there is a preferred method by which a slurry containing at leastinorganic color pigment particles (titanium oxide pigment, or the like),and extender pigment particles, as well as an inorganic compound sourceand/or an organic compound is prepared, and with stirring at least theinorganic color pigment particles and the extender pigment particles arefixed by the inorganic compound and/or organic compound, so that a finecomposite pigment having a median diameter D50 and a diameter oncumulative 90% (D90) within the above ranges can be easily produced.

Specifically, inorganic color pigment particles (titanium oxide pigment,or the like) and extender pigment particles (calcium carbonate, bariumsulfate, or the like) and the like, as well as an inorganic compoundsource are added to a solvent such as water, and dispersed by adisperser or the like to form a slurry.

As inorganic color pigment particles, inorganic color pigment particlescontaining zinc element may be used. In this regard, “containing zincelement” includes not only a state in which zinc element exists in theparticle surface of an inorganic color pigment but also a state in whichzinc element is present inside the particle of an inorganic colorpigment. An inorganic color pigment containing zinc element may beprepared as follows.

For example, a zinc compound is precipitated on the surface of theinorganic color pigment particles by adjusting the pH of a slurrycontaining the inorganic color pigment particles and the zinc compoundsource. As the zinc compound source, one capable of precipitating adesired zinc compound by pH adjustment can be used. For example, byusing zinc sulfate heptahydrate, zinc chloride, or the like as the zinccompound source, and adjusting the pH of the slurry to about 8 or moreand 8.5 or less, an oxide and/or a hydroxide of zinc can be precipitatedon the surface of the inorganic color pigment particles. At this time,an alkali such as sodium hydroxide can be used for pH adjustment.

Also, inorganic color pigment particles having zinc element on thesurface of the particle or inside the particle may be prepared by mixinginorganic color pigment particles and a zinc compound, and heating(calcination) this mixture. The addition amount of the zinc compound andthe temperature of heating (calcination) may be appropriately setaccording to the type of the inorganic color pigment and the like.

Further, when a titanium dioxide pigment is used as an inorganic colorpigment, a titanium dioxide pigment having a zinc compound on theparticle surface may be also prepared as follows. That is, a hydrate oftitanium dioxide, and a zinc compound as an additive for calcination aremixed and calcined. The amount of the zinc compound is preferably 0.1%by mass or more and 2.0% by mass or less in terms of ZnO with respect totitanium dioxide. Although the calcination conditions can be setappropriately, the calcination temperature is preferably 800° C. or moreand 1000° C. or less. As the additive for calcination, various zinccompounds may be used, but it is preferable to use an oxide and/orhydroxide of zinc.

The “inorganic compound source” means herein a material, whichprecipitates as an inorganic compound by adjusting the pH of a slurry asdescribed later. Examples of such an inorganic compound source includesodium silicate, sodium aluminate, aluminum sulfate, zirconium sulfate,stannous chloride, and titanium tetrachloride. As the inorganic compoundsource sodium silicate is preferable, and any of No. 1, No. 2 and No. 3defined in JIS 1408-1966 can be used, but use of No. 3 is preferablefrom the viewpoint of availability and handling.

In preparing the slurry, the volume ratio (Va/Vb) of the volume (Va) ofthe inorganic compound source to the volume (Vb) of the inorganic colorpigment particles and the extender pigment particles is preferably setat 0.3 or more and 2 or less. In this case, the volume (Va) of theinorganic compound source means the volume in terms of an inorganiccompound to be precipitated as a result of the pH adjustment describedlater. By adjusting to such a volume ratio, a sufficient fixation effectof the inorganic compound can be obtained, so that the composite pigmentcan acquire an appropriate size (preferable particle size distribution).

In a case where the inorganic color pigment particles contain zincelement, even when the volume ratio (Va/Vb) is less than 0.3 (forexample, about 0.25), a composite pigment having an appropriate size(preferable particle size distribution) can be obtained.

Subsequently, by adjusting the pH of the slurry, an inorganic compoundderived from the inorganic compound source precipitates, and theinorganic color pigment particles and the extender pigment particles arefixed by the inorganic compound. The pH for precipitation of theinorganic compound may be appropriately set according to the extenderpigment particles and the inorganic compound source. For example, whencalcium carbonate is used as the extender pigment, it is preferable toadjust the pH at about 7.0 or more and 10.0 or less. When barium sulfateis used as the extender pigment, it is preferable to adjust the pH atabout 3.0 or more and 10.0 or less. Further, for example, when sodiumsilicate is used as the inorganic compound source, it is preferable toadjust the pH to 2 or more and 10 or less by adding dilute sulfuricacid. By doing so, it is possible to obtain a composite pigment havingan appropriate size (preferable particle size distribution) whilereducing the formation of free silica. In the pH adjustment by addingthe dilute sulfuric acid, the pH is preferably adjusted into a range of6 or more and 9 or less, and more preferably adjusted into a range of 7or more and 8 or less. Further, it is preferable that the inorganiccompound is precipitated while heating the slurry and keeping thetemperature at about 50° C. or more and 100° C. or less.

After that, if necessary, dehydration and washing, then drying, andoptionally grinding are carried out by publicly known methods to producea composite pigment of the present invention. Further, if necessary, theabove dried product may be calcined at a higher temperature. Thecalcination temperature may be appropriately set, for example,preferably in an approximate range of 300° C. or more and 900° C. orless.

In the foregoing, the specific method of fixing the inorganic colorpigment particles and the extender pigment particles by an inorganiccompound has been described, but it is also possible to fix theinorganic color pigment particles and the extender pigment particles byan organic compound. More particularly, the extender pigment particles,the inorganic color pigment particles, and an organic compound (anorganic flocculant, an organic coagulant, or the like composed of apolymer compound, such as a cationic polymer, an anionic polymer, and anonionic polymer) are added to a solvent such as water, and dispersed bya dispersing machine such as a disperser to form a slurry, so that theinorganic color pigment particles and the extender pigment particles arefixed. By doing so, a composite pigment in which the inorganic colorpigment particles and the extender pigment particles are fixed by theorganic compound can be produced.

The composite pigment of the present invention produced by any ofvarious methods described above may be classified for the purpose ofremoving coarse particles. Classification may be carried out by grindingor sieving. There is no particular restriction on the classificationmethod by grinding, and examples thereof include an atomizer method.Examples of the classification method by sieving include wetclassification, and dry classification.

When the composite pigment of the present invention is furthersurface-treated with an inorganic compound and/or organic compound, thesurface treatment may be carried out by a publicly known method such asa wet process or a dry process. At this time, in order not to break theproduced composite pigment, it is preferable to avoid a treatment methodinvolving a high torque. For example, in a wet process, a compositepigment of the present invention may be surface-treated with aninorganic compound and/or organic compound by adding water or an organicsolvent to a composite pigment of the present invention, and aninorganic compound and/or organic compound, followed by mixing.

The composite pigment of the present invention can be used in variousapplications. For example, it may be used favorably as a matting agentto be blended in a paint composition for coating building wall surface(exterior, interior, ceiling, floor and bathtub, walls and floors ofkitchen, toilet, and the like), for coating building materials, forcoating vehicles, for coating furniture, and for coatingelectromechanical products. Further, the composite pigment of thepresent invention can be blended as a matting agent in plastic, rubber,latex, elastomer, and the like. In using it as a matting agent, thecomposite pigment of the present invention itself may be used, or ablend with a conventional matting agent, a color material, an additive,or the like may be used. Further, the composite pigment of the presentinvention may be blended as an extender, an additive, a filler, anextender pigment, a flowability-imparting agent, a strength enhancingauxiliary material, or an improver for optical properties in variouspaint compositions, plastic, rubber, latex, elastomer, ceramics, glass,metal, or the like.

A paint composition of the present invention contains theabove-described composite pigment and a resin, and if necessary,contains a color material, a dispersant, an additive, a solvent, and thelike.

Examples of the resin contained in the paint composition of the presentinvention include various resins for a paint, such as a phenolic resins,an alkyd resins, an acrylic alkyd resin, an acrylic resin, an acrylicemulsion resin, a polyester resin, a polyester-urethane resin, apolyether resin, a polyolefin resin, a polyurethane resin, an acrylicurethane resin, an epoxy resin, a modified epoxy resin, a siliconeresin, an acrylic silicone resin, and a fluorocarbon polymer.

As a color material, a pigment, a dye, and the like may be used. As thepigment to be contained in the paint composition of the presentinvention, various inorganic pigments (such as titanium dioxide, zincoxide, basic lead carbonate, lower titanium oxide, titanium oxynitride(titanium black), carbon black, bone black (bone charcoal), graphite,iron black, cobalt chromate black spinel, iron chromate composite oxide,copper chromate spinel black composite oxide, Fe—Mn—Bi black, red ironoxide, molybdenum red, nickel antimony titanium yellow, chrome antimonytitanium buff, synthetic iron oxide yellow, chrome yellow, ultramarineblue, iron blue, cobalt blue, cobalt green, chrome green, chromium oxidegreen, cobalt chromate green spinel, and cobalt titanate green spinel),and various organic pigments (such as lake red 4R, ITR red, naphtholred, pyrazolone orange, pyrazolone red, benzimidazolone orange, watchingred, lake red R, bordeaux 10B, bon maroon light, anthraquinone red,dianthraquinone red, anthanthrone red, anthanthrone orange, perylenered, perylene maroon, perylene violet, perinone orange, quinacridonered, quinacridone violet, quinacridone magenta, dimethylmagenta,dichloroquinacridone magenta, dichloromagenta, quinacridone maroon,quinacridone scarlet, diketopyrrolopyrrole, fast yellow, benzimidazoloneyellow, diarylide yellow, isoindoline yellow, quinophthalone yellow,phthalocyanine green, chlorinated phthalocyanine green, brominatedphthalocyanine green, phthalocyanine blue, threne blue, and dioxazineviolet) may be used. As the dye, a basic dye (such as rhodamine, bismarcgreen, malachite green, and methyl violet), a direct dye (such as congored, and direct scarlet), an acid dye (such as metanil yellow,nigrosine, and acid fast red), a metal complex dye, an oil-soluble dye,and the like may be used. At least one selected from these colormaterials may be used.

Further, a transparent (translucent) matting paint is prepared, if acolor material is not blended in a paint composition. Such a transparent(translucent) matting paint may be used as a topcoat, which is coated ona base layer (a layer formed by coating a color gloss paint, or a pearlpaint to a substrate) in the application field of vehicles, or the like.

Examples of an additive contained in the paint composition of thepresent invention include various kinds of commonly used emulsifiers,antifreezing agents, pH adjusters, thickeners, and defoaming agents.Examples of a solvent include water, toluene, xylene, mineral spirit,acetone, methyl ethyl ketone, methanol, butanol, ethyl acetate, amineacetate, and ethylene glycol. A dispersant is appropriately selectedaccording to the type of an inorganic compound having been used forsynthesizing the composite pigment. For example, since silica is presenton the surface of the composite pigment when silica is used as theinorganic compound, the surface is slightly acidic. In this case, it ismore preferable to use a dispersant having a certain amine value as thedispersant. Specifically, there are “DISPERBYK (registeredtrademark)-183”, “DISPERBYK (registered trademark)-184”, “DISPERBYK(registered trademark)-185” manufactured by BYK Additives & Instruments,and the like.

When the paint composition of the present invention is processed to amatting paint by adding a composite pigment of the present invention toa gloss paint or otherwise, the addition amount of the composite pigmentis preferably adjusted in a range of 0.1% by mass or more and 10% bymass or less, and further preferably at 1% by mass or more and 5% bymass or less.

In a case where a matting paint for a transparent (translucent) topcoatis prepared by adding a color material at a minimal content, or addingno color material, the pigment volume concentration (PVC) of thecomposite pigment is preferably adjusted in a range of 5% or more and40% or less, more preferably in a range of 10% or more and 30% or less,and further preferably in a range of 15% or more and 25% or less. Byadjusting in such a range, it is possible to prepare a matting paint fora topcoat, which can sufficiently reduce a gloss, while keeping color ofthe base layer.

The composite pigment containing the inorganic color pigment particlesof the present invention can be used in various applications as a colorpigment (matting pigment) having low-gloss property (matte effect). Forexample, it may be used favorably as a matting pigment to be blended ina paint composition for coating building wall surface (exterior,interior, ceiling, floor and bathtub, walls and floors of kitchen,toilet, and the like), for coating building materials, for coatingautomobiles, for coating furniture, and for coating electromechanicalproducts. Such a matting pigment may be used as blended in variouspaints in place of so-called matting agent (a component for developing amatte effect to be added into a paint separately from the colormaterial).

The paint composition of the present invention contains the compositepigment and/or the matting pigment, and the resin, as well as, ifnecessary, also the additive, solvent, dispersant, or the like.

When the composite pigment of the present invention contains theinorganic color pigment particles, it functions by itself also as acolor material. Therefore, when a paint composition of the presentinvention is prepared, it is not necessary to add separately a colormaterial, but it is also possible to add a color material separately inaddition to the composite pigment. As the color material, theabove-mentioned common pigments, dyes and the like may be used.

The pigment volume concentration (PVC) of the paint composition of thepresent invention is preferably adjusted in a range of 10% or more and60% or less. When importance is attached to reduction of the gloss of apaint film, it is more preferable to adjust the pigment volumeconcentration in the lower side of the above range, namely in a range of20% or more and 40% or less, and further preferably in a range of 30% ormore and 40% or less. Further, when importance is attached to the hidingpower of a paint film, it is more preferable to adjust the pigmentvolume concentration in the upper side of the above range, namely in arange of 50% or more and 60% or less.

The composite pigment and the resin, and if necessary theabove-mentioned dispersant, additive, solvent, color material, and thelike are stirred with a dispersing machine, and if necessary degassingis performed, to prepare a paint composition of the present invention.

A paint film of the present invention is formed by coating theaforedescribed paint composition onto an object and curing it. That is,a paint film of the present invention may be obtained by coating theaforedescribed paint composition onto an object using a brush, a woolroller, or the like, followed by drying. Examples of the object includebuilding materials (concrete, mortar, gypsum, plaster, plastic, glass,earthenware, stone, wood, and the like), a vehicle main body (metallic,or plastic), furniture and electromechanical products (plastic, glass,earthenware, stone-made, wooden, and the like). The object may be coatedin advance with a paint composition different from the paint compositionof the present invention (gloss paint, pearl paint, or the like).

EXAMPLES

Hereinafter, the present invention (the first invention of the presentapplication to the fifth invention of the present application) will bedescribed in detail in accordance with Examples and ComparativeExamples, but the present invention is not limited to the Examples.

Examples of the Invention (the First Invention of the PresentApplication) Example 1-1

135 g of barium sulfate (TS-2 manufactured by Takehara Kagaku Kogyo Co.,Ltd., average primary particle diameter: 0.3 μm) was dispersed in 705 gof pure water, 231 g of No. 3 sodium silicate aqueous solution wasadded, and the resulting mixture was mixed to prepare a barium sulfateslurry containing sodium silicate. The volume ratio (Va/Vb) of a volumeVa of sodium silicate (in terms of SiO₂) to a volume Vb of bariumsulfate in the slurry was 1. The solution was put in a reaction vesselequipped with a stirrer and a thermometer, and was heated to 75° C. withstirring. While the liquid temperature was kept at 75° C., 2.0% by masssulfuric acid was added over 3 hours using a microtube pump (MP-2001manufactured by Tokyo Rikakikai Co., Ltd.), so that the solution had apH of 7.5. Subsequently, the solution was aged for 1 hour to obtainaggregates of barium sulfate with silica as a binder in a solution.Further, the solution was filtered using No. 2 filter paper, and solidsremaining on the filter paper were washed with water, and filtered toobtain a wet filter cake of the aggregates. The obtained wet filter cakewas heated and dried for 16 hours in a drier set at 120° C. Thethus-obtained dry powder of the aggregates was subjected to dry grindingusing a grinder (Stud Mill 63Z manufactured by Makino Mfg. Co., Ltd.),and then classified (rotation speed: 3600 rpm, air flow: 1.5 m³/minute)by a classifier (TC-15M manufactured by Hosokawa Micron Corporation) toobtain a composite pigment in which barium sulfate was fixed withsilica. FIG. 1 shows an electron microscope photograph of the compositepigment of Example 1-1.

Example 1-2

As compared to Example 1-1 described above, the amount of a silicasource added was larger. Specifically, the amount of pure water used waschanged to 540 g, and the amount of No. 3 sodium silicate aqueoussolution added was changed to 462 g, so that a slurry was prepared inwhich the volume ratio (Va/Vb) of sodium silicate (in terms of SiO₂) tobarium sulfate was 2. Except for the above, the same procedure as inExample 1-1 was carried out to obtain a composite pigment in whichbarium sulfate was fixed with silica. FIG. 2 shows an electronmicroscope photograph of the composite pigment of Example 1-2.

Example 1-3

As compared to Example 1-1 described above, the amount of a silicasource added was smaller. Specifically, the amount of pure water usedwas changed to 788 g, and the amount of No. 3 sodium silicate aqueoussolution added was changed to 116 g, so that a slurry was prepared inwhich the volume ratio (Va/Vb) of sodium silicate (in terms of SiO₂) tobarium sulfate was 0.5. Except for the above, the same procedure as inExample 1-1 was carried out to obtain a composite pigment in whichbarium sulfate was fixed with silica. FIG. 3 shows an electronmicroscope photograph of the composite pigment of Example 1-3.

Example 1-4

As compared to Example 1-1 described above, the amount of a silicasource added was smaller, and even smaller than that in Example 1-3.Specifically, the amount of pure water used was changed to 829 g, andthe amount of No. 3 sodium silicate aqueous solution added was changedto 58 g, so that a slurry was prepared in which the volume ratio (Va/Vb)of sodium silicate (in terms of SiO₂) to barium sulfate was 0.25. Exceptfor the above, the same procedure as in Example 1-1 was carried out toobtain a composite pigment in which barium sulfate was fixed withsilica. FIG. 4 shows an electron microscope photograph of the compositepigment of Example 1-4.

(Evaluation of Physical Properties of Powder)

For the composite pigments of the various Examples, various powderphysical properties (particle size distribution, specific surface areaand oil absorption) were measured. The results thereof are shown inTable 1-1. Table 1-1 also shows the powder physical properties ofextender pigments that are commonly used as a matting agent, a silicamatting agent, and a resin bead matting agent. Specifically, Table 1-1shows the results of measurement of various powder physical propertiesfor barium sulfate (W-1 manufactured by Takehara Kagaku Kogyo Co., Ltd.,average particle diameter: 1.5 μm) in Comparative Example 1-1, bariumsulfate (W-6 manufactured by Takehara Kagaku Kogyo Co., Ltd., averageparticle diameter: 4.5 μm) in Comparative Example 1-2, barium sulfate(W-10 manufactured by Takehara Kagaku Kogyo Co., Ltd., average particlediameter: 10 μm) in Comparative Example 1-3, silica (Sylysia 276manufactured by Fuji Silysia Chemical Ltd., average particle diameter: 7μm) in Comparative Example 1-4), and resin beads (ART PEARL G-800manufactured by Negami Chemical Industrial Co., Ltd., average particlediameter: 6 μm) in Comparative Example 1-5.

The methods for measurement of various powder physical properties are asfollows. In the measurement methods described below, the “sample” refersto a composite pigment in each of the Examples or a matting agent ineach of the Comparative Examples.

(Measurement of Particle Size Distribution)

A particle size distribution was measured using a laserdiffraction/scattering-type particle size distribution measuringapparatus (LA-910 manufactured by HORIBA, Ltd.). Specifically, anaqueous solution in which 0.3% by mass of sodium hexametaphosphate wasdissolved was prepared as a dispersion medium, each sample was mixed inthe aqueous solution, the resulting mixture was circulated and stirredin the apparatus, and simultaneously irradiated with an ultrasonic wavefor 3 minutes to sufficiently disperse the sample, and adjustment wasperformed so that the transmittance of laser light was 73±3%, followedby measuring a particle size distribution on the volume basis. Here, therelative refractive index (complex refractive index) was set to1.6-0.00i for the Examples and Comparative Examples 1-1 to 1-3, and1.5-0.00i for Comparative Examples 1-4 and 1-5, and the number ofcaptures was 10.

From the particle size distribution data obtained in this manner, theparticle size distribution was expressed as a cumulative distribution,and the particle diameter at cumulative 50% was defined as a diameter oncumulative 50% (D50). Similarly, the particle diameter at cumulative 10%was defined as a cumulative 10% diameter (D10), and the particlediameter at cumulative 90% was defined as a diameter on cumulative 90%(D90). In FIG. 5, a volume cumulative particle size distribution diagramfor the composite pigment of Example 1-1 is shown as a representative ofthe various Examples.

(Measurement of Specific Surface Area)

A BET specific surface area was measured by a nitrogen adsorption methodusing a BET specific surface area measuring apparatus “MONOSORB”(manufactured by Yuasa-Ionics Co., Ltd.).

(Measurement of Oil Absorption)

Measurement was performed in accordance with Pigment Test MethodJIS-K5101-13-1: 2004. Specifically, 5 g of a sample was put on a smoothglass plate, boiled linseed oil was dropped from a burette, and theresulting mixture was generally kneaded with a pallet knife at all suchtimes. The dropping and the kneading were repeated, and a point at whichit was possible to wind the mixture in a spiral form using the palletknife was defined as an end point. The amount of boiled linseed oilabsorbed in each sample was divided by the mass of the sample tocalculate an oil absorption. In Table 1-1, the oil absorption isexpressed in a unit of ml/100 g.

TABLE 1-1 Particle size distribution Specific Oil D10 D50 D90 surfacearea absorption (μm) (μm) (μm) (m²/g) (ml/100 g) Example 1-1 1.7 5.612.9 63.9 53 Example 1-2 2.4 8.4 19.1 64.2 86 Example 1-3 1.5 4.5 10.855.1 47 Example1-4 0.8 1.3 2.3 9.2 —(Not measured) Comparative 1.3 3.09.4 1.7 10 Example 1-1 Comparative 2.0 4.7 12.9 0.7 10 Example 1-2Comparative 2.2 9.4 23.3 0.8 10 Example 1-3 Comparative 4.3 7.4 12.2191.6 180  Example 1-4 Comparative 3.0 7.4 13.5 3.5 36 Example 1-5(Preparation of Paint Composition)

A transparent matting paint composition was prepared using the compositepigment in each of the above Examples and the matting agent in each ofthe above Comparative Examples. The pigment volume concentration (PVC)of the paint composition was set to 20%, and the solid volumeconcentration (SVC) of the paint composition was set to 30%.Specifically, raw materials were blended at a ratio in Table 1-2 below,and the resulting mixture was stirred for 5 minutes using a dispersingmachine (T.K. ROBOMIX manufactured by Tokushu Kika Kogyo Co., Ltd.,rotation speed: 3000 rpm), and then defoamed by a hybrid mixer (HM-500manufactured by KEYENCE CORPORATION) to obtain a transparent mattingpaint composition.

For the transparent matting paint compositions in Examples 1-1 to 1-4and Comparative Examples 1-1 to 1-5, the samples of the correspondingExamples and Comparative Examples were used, respectively, as mattingagents. In addition, for the transparent matting paint composition inComparative Example 1-6, a mixture of the barium sulfate matting agentin Comparative Example 1-1 and the silica matting agent in ComparativeExample 1-4 at a volume ratio of 1:1 was used as a matting agent. Forthe transparent matting paint composition in Comparative Example 1-7, amixture of the barium sulfate matting agent in Comparative Example 1-2and the silica matting agent in Comparative Example 1-4 at a volumeratio of 1:1 was used as a matting agent. For the transparent mattingpaint composition in Comparative Example 1-8, a mixture of the bariumsulfate matting agent in Comparative Example 1-3 and the silica mattingagent in Comparative Example 1-4 at a volume ratio of 1:1 was used as amatting agent.

TABLE 1-2 Examples 1-1~1-4, Comparative Comparative ComparativeComparative Examples Example Example Example 1-6~1-8 1-1~1-3 1-4 1-5Resin Acrylic emulsion resin, 43.5 parts 40.7 parts 46.4 parts 49.3parts PRIMAL AC-2235 by mass by mass by mass by mass manufactured byRohm and Haas Japan K.K. Dispersant DISPERBYK-184 0.5 parts 0.7 parts0.4 parts 0.2 parts manufactured by by mass by mass by mass by mass BYKAdditives & Instruments (amine value: 15 mg KOH/g) Pure water 7.8 parts7.5 parts 8.1 parts 8.4 parts by mass by mass by mass by mass EmulsifierTRITON CF-10 0.8 parts 0.8 parts 0.9 parts 0.9 parts manufactured by bymass by mass by mass by mass Dow Chemical Company Antifreezing Ethyleneglycol 7.1 parts 6.7 parts 7.6 parts 8.1 parts Agent manufactured by bymass by mass by mass by mass Kanto Chemical Co., Inc. pH adjuster 28%ammonia aqueous solution 0.2 parts 0.2 parts 0.2 parts 0.3 parts by massby mass by mass by mass Thickener 2% CELLOSIZE aqueous 22.4 parts 21.0parts 23.9 parts 25.4 parts solution manufactured by by mass by mass bymass by mass Dow Chemical Company Defoaming ADEKANATE B-748A 0.1 parts0.1 parts 0.2 parts 0.2 parts Agent manufactured by by mass by mass bymass by mass ADEKA CORPORATION Sample 17.6 parts 22.3 parts 12.3 parts7.2 parts by mass by mass by mass by mass(Measurement of Viscosity of Paint)

For the transparent matting paint composition in each of the Examplesand Comparative Examples, a viscosity was measured using a BrookfieldB-type rotary viscometer (TVB-10 Viscometer manufactured by Toki SangyoCo., Ltd.). The measurement results are shown in Table 1-3. Themeasurement was performed under the following conditions. The paintcomposition was put in a 50 ml graduated cylinder, and the viscosity wasmeasured at each of the rotation speeds (6 rpm and 60 rpm).

Rotor: TM4

Measurement temperature: 25° C.

TABLE 1-3 Viscosity (Pa · s) 6 rpm 60 rpm Example 1-1 8.9 1.7 Example1-2 17.2 3.2 Example 1-3 10.6 2.1 Example 1-4 9.4 1.9 ComparativeExample 1-1 5.3 1.1 Comparative Example 1-2 4.9 1.1 Comparative Example1-3 4.4 0.9 Comparative Example 1-4 30.7 5.7 Comparative Example 1-5 5.01.0 Comparative Example 1-6 12.5 2.5 Comparative Example 1-7 12.2 2.4Comparative Example 1-8 12.6 2.6

The paint composition in each of the various Examples had a viscositylower than that of the paint composition in Comparative Example 1-4using silica as a matting agent, and exhibited good handling. Theviscosity (handling) of the paint composition in each of the Exampleswas equal to or lower than the viscosity (handling) of the paintcomposition (in each of Comparative Examples 1-6 to 1-8) using a mixtureof silica and barium sulfate as a matting agent, and the paintcomposition in each of the Examples attained low viscosity (highhandling) substantially comparable to that of the paint composition (ineach of Comparative Examples 1-1 to 1-3 and 1-5) using an extenderpigment (barium sulfate), resin beads or the like as a matting agent.

(Evaluation of Physical Properties of Paint Film)

For the transparent matting paint composition in each of the Examplesand Comparative Examples, the physical properties of a paint film wereevaluated. The results thereof are shown in Table 1-4. Methods formeasurement of various physical properties of a paint film are asfollows.

(Measurement of Gloss)

The gloss of a paint film obtained by applying and drying thetransparent matting paint composition in each of the above Examples andComparative Examples was measured in accordance with JIS K5600-4-7:1999. First, using a four-mill film applicator, the transparent mattingpaint composition was applied onto a glass plate in such a manner thatthe thickness was about 40 μm. The applied composition was dried, and aspecular gloss was then measured at each of 20°, 60° and 85° using aglossmeter (haze-gloss meter manufactured by BYK-Gardner GmbH).

(Measurement of Hiding Power)

The hiding power of a paint film obtained by applying and drying thetransparent matting paint composition in each of the above Examples andComparative Examples was measured in accordance with JIS K5600-4-1:1999. First, using a four-mill film applicator, the paint compositionwas applied onto a test paper for the hiding power in such a manner thatthe thickness was about 40 μm. The applied composition was dried, and aY_(b) value (Y value of black part) and a Y_(w) value (Y value of whitepart) were then measured using a spectral colorimeter (SD 5000manufactured by Nippon Denshoku Industries Co., Ltd.). From the Y_(b)value and the Y_(w) value, a hiding power (thereinafter, referred to asC.R.) was calculated in accordance with the following equation.C.R. (%)=Y _(b) value/Y _(w) value×100

TABLE 1-4 Hiding power Gloss C.R. 20° 60° 85° Yb Yw (%) Example 1-1 0.55.0 4.8 6.8 81.3 8.3 Example 1-2 0.4 3.0 2.7 10.6 80.9 13.0 Example 1-30.5 3.3 5.1 9.5 81.1 11.7 Example 1-4 0.5 4.1 40.7 7.0 81.6 8.6Comparative Example 1-1 1.5 16.7 30.8 4.6 80.1 5.7 Comparative Example1-2 0.8 9.4 10.6 5.0 80.9 6.1 Comparative Example 1-3 1.2 13.0 11.0 4.880.9 5.9 Comparative Example 1-4 0.4 3.3 6.1 9.4 81.2 11.6 ComparativeExample 1-5 1.5 13.8 6.6 4.3 81.4 5.3 Comparative Example 1-6 0.4 5.55.9 5.5 80.8 6.8 Comparative Example 1-7 0.4 5.8 6.3 5.2 81.3 6.4Comparative Example 1-8 0.5 6.9 5.9 5.2 81.4 6.4

As compared to the paint films of the transparent matting paintcompositions in Comparative Examples 1-1 to 1-3 (matting agents ofbarium sulfate), Comparative Example 1-5 (matting agent of resin beads)and Comparative Examples 1-6 to 1-8 (mixed matting agents of bariumsulfate and silica), the paint film of the transparent matting paintcomposition in each of the Examples had a smaller specular gloss at 20°and 60°, and apparently reduced gloss, and exhibited a sufficient matteeffect. The low-gloss property (matte effect) in each of the Exampleswas comparable to that in Comparative Example 1-4 with a high matteeffect, and a gloss was reduced even to the degree of a gloss reductionreferred to as “matting (specular gloss of 5% or less at 60°)” over thedegree of a gloss reduction generally referred to as “70% gloss”, “50%gloss” or “30% gloss”.

In addition, in the paint films of the transparent matting paintcompositions in Examples 1-1 to 1-3, the specular gloss at 85° wasreduced to 10% or less, and so-called 85° gloss was sufficientlyreduced.

Further, the paint films of the transparent matting paint compositionsin the Examples had substantially the same hiding power as in theComparative Examples, and maintained a low hiding power. Suchtransparent matting paint compositions do not hinder color of the baselayer even when applied onto a color base layer, and is thereforeappropriate as a topcoat matting paint composition which is applied ontothe color base layer.

(Evaluation of Uneven Loss of Gloss of Paint Film)

Uneven loss of gloss of the paint film obtained by applying and dryingthe transparent matting paint composition in each of the above Examplesand Comparative Examples was evaluated in the following manner. Thespecular gloss (20°, 60° and 85°) at each of five arbitrary spots wasmeasured for the paint film used for measurement of the gloss. Astandard deviation for the five spots was calculated. The calculationresults are shown in Table 1-5.

TABLE 1-5 Uneven loss of gloss 20° 60° 85° Example 1-1 0.0 0.3 0.1Example 1-2 0.1 0.5 0.1 Example 1-3 0.1 0.3 0.3 Example 1-4 0.1 0.6 1.7Comparative Example 1-1 0.1 1.4 1.4 Comparative Example 1-2 0.0 0.4 1.1Comparative Example 1-3 0.2 0.5 2.0 Comparative Example 1-4 0.1 0.4 0.5Comparative Example 1-5 0.0 0.3 0.2 Comparative Example 1-6 0.1 0.7 0.2Comparative Example 1-7 0.1 1.3 0.1 Comparative Example 1-8 0.1 0.6 0.1

The values of the specular gloss (20°, 60° and 85°) in Table 1-5generally correlated with impressions of appearance (uneven loss ofgloss) of the actual paint films, and uneven loss of gloss of the paintfilm tended to increase as the numerical value of the standard deviationbecame larger. Specifically, the paint films in Comparative Examples 1-1to 1-3, which contained barium sulfate alone, had noticeable uneven lossof gloss of the paint film. On the other hand, as is the case with thepaint films in the other Comparative Examples, the paint films inExamples 1-1 to 1-4 had no uneven loss of gloss, and confirmed touniformly have a reduced gloss at every location on the paint film.

(Evaluation of Tactile Feeling of Paint Film)

For the paint film obtained by applying and drying the paint compositionin each of the Examples and Comparative Examples, smoothness of tactilefeeling was evaluated.

For quantifying the tactile feeling of the paint film as objective data,a friction coefficient was measured. Specifically, using a four-millfilm applicator, the paint composition was applied onto a glass plate insuch a manner that the thickness was about 40 The applied compositionwas dried, and an MMD (mean friction coefficient variation) was thenmeasured using a friction feeling tester (KES-SE manufactured by KatoTech Co., Ltd.). The MMD (mean friction coefficient variation) is usedas an index indicating a feeling of roughness of the paint film. Themeasurement results are shown in Table 1-6. In Table 1-6, tactilefeeling at the time of actually touching the paint film with a finger isshown in three grades (∘: smooth tactile feeling, Δ: rough tactilefeeling, X: highly rough tactile feeling) along with the value of theaforementioned MMD.

TABLE 1-6 Tactile MMD feeling Example 1-1 0.0105 ◯ Example 1-2 0.0100 ◯Example 1-3 0.0070 ◯ Example 1-4 0.0066 ◯ Comparative Example 1-1 0.0285X Comparative Example 1-2 0.0207 Δ Comparative Example 1-3 0.0664 XComparative Example 1-4 0.0190 ◯ Comparative Example 1-5 0.0075 ◯Comparative Example 1-6 0.0291 Δ Comparative Example 1-7 0.0202 ΔComparative Example 1-8 0.0262 Δ

All the paint films of the paint compositions in the various Exampleshad a better (smoother) tactile feeling as compared to the paint filmsin the Comparative Examples (Comparative Examples 1-1 to 1-3 andComparative Examples 1-6 to 1-8), which contained an extender pigment(barium sulfate). The degree of the smoothness was equal to or greaterthan that of a paint film having a smooth tactile feeling in generallike the paint films which contained silica or resin beads as a mattingagent (in Comparative Examples 1-4 and 1-5).

As described above, paint compositions and paint films containing thecomposite pigment in these Examples are excellent in that they maintaingood handling, has a low-gloss property (matte effect), and can attain agood tactile feeling of the paint film.

Examples of the Present Invention (the Second Invention of the PresentApplication) Example 2-1

129 g of a titanium dioxide pigment (manufactured by Ishihara SangyoKaisha, Ltd., average primary particle diameter: 0.24 μm) and 82.8 g ofa precipitated (synthesized) calcium carbonate (extender pigment,Brilliant-1500, manufactured by Shiraishi Calcium Kaisha, Ltd., averageprimary particle diameter: 0.15 μm) were dispersed in 819.6 g of purewater. 116.4 g of a No. 3 sodium silicate aqueous solution was added tothe solution and mixed to prepare a sodium silicate solution containingthe titanium dioxide pigment and calcium carbonate. The solution wascharged in a reaction vessel equipped with a stirrer and a thermometer,and heated up to 75° C. under stirring. While the solution temperaturewas held at 75° C., a sulfuric acid of 1.8% by mass was added over 3hours by using a microtube pump (MP-2001 manufactured by Tokyo RikakikaiCo., Ltd.) to make pH of the solution to be 7.0 to 7.5. Thereafter, thesolution was aged for 1 hour to thereby obtain a composite pigment oftitanium dioxide and calcium carbonate with silica as a binder in thesolution. The solution was filtered by using a No. 2 filter paper, andsolids remaining on the filter paper were washed with water, and againfiltered to thereby obtain a wet filter cake of the above compositepigment. The obtained wet filter cake was heated and dried for 16 hoursin a drier set at 120° C. The thus-obtained dry powder of the compositepigment was dry ground by using a grinder (Stud Mill 63Z manufactured byMakino Mfg. Co., Ltd.), and thereafter classified (rotation speed: 3,600rpm, air flow: 1.5 m³/min) by using a classifier (TC-15M manufactured byHosokawa Micron Corporation) to obtain a composite pigment. An electronmicroscope photograph of the composite pigment of Example 2-1 is shownin FIG. 6, and an enlarged view of FIG. 6 is shown in FIG. 7. Ahigher-magnification enlarged view of FIG. 7 is shown in FIG. 32.

Example 2-2

A composite pigment of titanium dioxide and calcium carbonate withsilica as a binder was obtained by the same procedure as in Example 2-1described above, except for changing the amount of calcium carbonateused to 165.6 g. An electron microscope photograph of the compositepigment of Example 2-2 is shown in FIG. 8.

Example 2-3

A composite pigment of titanium dioxide and calcium carbonate withsilica as a binder was obtained by the same procedure as in Example 2-1described above, except for changing the amount of calcium carbonateused to 41.4 g. An electron microscope photograph of the compositepigment of Example 2-3 is shown in FIG. 9.

Example 2-4

A composite pigment of titanium dioxide and calcium carbonate withsilica as a binder was obtained by the same procedure as in Example 2-1described above, except for changing the amount of pure water used to733.7 g and the amount of the sodium silicate aqueous solution used to232.8 g. An electron microscope photograph of the composite pigment ofExample 2-4 is shown in FIG. 10.

Example 2-5

A composite pigment of silica, titanium dioxide and calcium carbonatewas obtained in a solution by the same procedure as in Example 2-1described above, and thereafter, 21.8 ml of a sodium aluminate aqueoussolution (300 g/L) was added to the solution by using a microtube pump(MP-2001 manufactured by Tokyo Rikakikai Co., Ltd.). At this time,sulfuric acid was simultaneously added to hold pH of the solution at 7.0to 7.5. Thereafter, the solution was aged for 30 min to thereby obtain,in the solution, a composite pigment which consists of silica, titaniumdioxide and calcium carbonate and has a cover layer of alumina formed onits surface. The solution was further filtered by using a No. 2 filterpaper, and solids remaining on the filter paper were washed with water,and again filtered to thereby obtain a wet filter cake of the abovecomposite pigment. The obtained wet filter cake was heated and dried for16 hours in a drier set at 120° C. The thus-obtained dry powder of thecomposite pigment was dry ground by using a grinder (Stud Mill 63Zmanufactured by Makino Mfg. Co., Ltd.), and thereafter classified(rotation speed: 3,600 rpm, air flow: 1.5 m³/min) by using a classifier(TC-15M manufactured by Hosokawa Micron Corporation) to obtain acomposite pigment. An electron microscope photograph of the compositepigment of Example 2-5 is shown in FIG. 11.

Example 2-6

5 g of the composite pigment obtained in Example 2-1, 195 g of toluene(manufactured by Kanto Chemical Co., Inc.) and 50 g of a silicone resin(KR-251 manufactured by Shin-Etsu Chemical Co., Ltd.) were charged in areaction vessel, and stirred for 10 min by a paint shaker. After thefinish of the stirring, the resultant solution was treated by ahigh-speed refrigerated centrifuge (CR21GII manufactured by Hitachi,Ltd., rotation speed: 7,500 rpm) for 5 min to remove separated toluene,and heated and dried for 16 hours in a drier set at 120° C. There wasthus obtained a composite pigment of silica, titanium dioxide andcalcium carbonate, whose surface was covered with the silicone resin. Anelectron microscope photograph of the composite pigment of Example 2-6is shown in FIG. 12.

Example 2-7

A composite pigment of titanium dioxide and barium sulfate with silicaas a binder was obtained by the same procedure as in Example 2-1described above, except for using 138.4 g of a barium sulfate (extenderpigment, TS-2, manufactured by Takehara Kagaku Kogyo Co., Ltd., averageprimary particle diameter: 0.31 μm) in place of calcium carbonate inExample 2-1. An electron microscope photograph of the composite pigmentof Example 2-7 is shown in FIG. 13.

Comparative Example 2-1

A mixed powder was obtained by mixing titanium oxide and calciumcarbonate in the same ratio as in Example 2-1. An electron microscopephotograph of the mixed powder of Comparative Example 2-1 is shown inFIG. 14.

(Evaluation of Physical Properties of Powder)

For the composite pigments of the various Examples and the mixed powderof Comparative Example 2-1, various powder physical properties weremeasured as follows. The results are shown in Table 2-1. The measurementmethods of the various physical properties were as follows. In thefollowing description of the measurement methods, “sample” refers to acomposite pigment of the various Examples or the mixed powder ofComparative Example 2-1.

(Measurements of Median Diameter and Diameter on Cumulative 90%)

The median diameter and the diameter on cumulative 90% were measured byusing the laser diffraction/scattering-type particle size distributionmeasuring apparatus “LA-910” (manufactured by HORIBA, Ltd.). In detail,each sample was mixed in an aqueous solution as a disperse medium inwhich 0.3% by mass of sodium hexametaphosphate was dissolved, and whilebeing circulated and stirred in the apparatus, irradiated for 3 min withultrasonic waves to be sufficiently dispersed and adjusted so that thetransmittance of laser light became 73±3%, and thereafter, the particlesize distribution in terms of volume was measured. The relativerefractive index at this time was fixed at 2.00-0.00i and the number ofcaptures was made to be 10 times. When the particle size distributionwas expressed as cumulative distribution, the particle diameter atcumulative 50% was defined as a median diameter D50 and the particlediameter at cumulative 90% was defined as a diameter on cumulative 90%(D90).

(Measurement of Specific Surface Area)

The specific surface area was measured by a BET method using a specificsurface area measuring apparatus (Flowsorb 112300 manufactured byShimadzu Corp.). As a gas to be used for the measurement, a mixed gas ofnitrogen and helium containing 30% by volume of nitrogen as anadsorption gas and 70% by volume of helium as a carrier gas was used. Asample was filled in a cell, and heated and degassed by using a vacuumdevice, and thereafter, a certain amount of the mixed gas of nitrogenand helium was made to flow and the specific surface area was measured.

(Measurement of Oil Absorption)

The oil absorption was measured according to the pigment test methodJIS-K5101-13-1: 2004. In detail, 5 g of a sample was put on a smoothglass plate; and a boiled linseed oil was dropped from a burette and theentire mixture was kneaded by a pallet knife every dropping. Thedropping and kneading were repeated, and a point at which the mixturecame to have a state of being capable of being spirally wound by usingthe pallet knife was defined as an end point. The amount of the boiledlinseed oil absorbed in each sample was divided by the mass of eachsample to calculate an oil absorption. In the present invention, the oilabsorption is expressed in a unit of ml/100 g.

(Measurements of Compositions of Composite Pigments and the Like)

The composition of the constituent components of each sample wasmeasured by using an X-ray fluorescence analyzer (RIX-2100 manufacturedby Rigaku Corp.). In detail, a sample was packed in an aluminum ring,and pressure molded by an oil pressing machine to make a sample for themeasurement.

In Table 2-1, based on the measurement results, there were calculatedcompositions (mass ratios) of the titanium oxide, the calcium carbonate(or the barium sulfate) and the silica which were contained in acomposite pigment. Specifically, masses of the titanium oxide in termsof TiO₂, the calcium carbonate in terms of CaCO₃, the barium sulfate interms of BaSO₄ and the silica in terms of SiO₂ were totaled and taken as100, and the each mass ratio was calculated.

TABLE 2-1 Specific surface Oil D50 D90 area absorption Composition (massratio) (μm) (μm) (m²/g) (ml/100 g) TiO₂ CaCO₃ BaSO₄ SiO₂ Example 2-1 1.41.8 21.5 44 64 25 — 11 Example 2-2 1.0 1.7 19.6 45 47 43 — 10 Example2-3 1.4 2.3 22.4 47 67 19 — 14 Example 2-4 1.4 2.5 27.2 52 55 27 — 18Example 2-5 1.8 3.3 28.8 50 61 24 — 15 Example 2-6 1.4 1.4 19.3 42 59 29— 12 Example 2-7 1.6 2.8 24.5 39 51 — 37 12 Comparative 0.6 0.9 14.2 2161 39 — — Example 2-1(Preparation of Paint Composition)

Paint compositions were prepared by using the composite pigments ofExamples 2-1 to 2-5 and Example 2-7 and the mixed powder of ComparativeExample 2-1. Specifically, the raw materials described in the followingTable 2-2 were stirred by using a dispersing machine (T.K. ROBOMIX,manufactured by Tokushu Kika Kogyo Co., Ltd., rotation speed: 3,000rpm), and then defoamed by a hybrid mixer (HM-500 manufactured byKEYENCE CORPORATION) to obtain the paint compositions.

TABLE 2-2 Resin Acryl emulsion resin, PRIMAL 33.4 parts AC-2235,manufactured by Rohm by mass and Haas Japan K.K. DispersantDISPERBYK-184 manufactured by 1.0 parts BYK Additives & Instruments bymass Tap water 4.2 parts by mass Emulsifier TRITON CF-10 manufactured by0.6 parts Dow Chemical Company by mass Antifreezing Ethylene glycol,manufactured by 5.5 parts agent Kanto Chemical Co., Inc. by mass Curingagent 28% ammonia aqueous solution 2.6 parts by mass Thickener 2%CELLOSIZE aqueous solution 17.3 parts manufactured by by mass DowChemical Company Defoaming ADEKANATE B-748A 0.1 parts agent manufacturedby ADEKA by mass CORPORATION Sample of 35.3 parts Example or by massComparative Example

The paint compositions thus obtained had a pigment volume concentration(PVC) of 40% and a solid volume concentration (SVC) of 36.4%.

Here, in the following description, the paint composition prepared bythe above-mentioned method using the sample of Example 2-1 was treatedas a paint composition of Example 2-1. The same is applied to the otherExamples and Comparative Examples.

In addition to the above paint compositions, the following were preparedas paint compositions of the Comparative Examples.

Comparative Example 2-2

A commercially available matting paint composition (ECOFLAT 60manufactured by Nippon Paint Co., Ltd.) was prepared.

Comparative Example 2-3

A matting paint composition was prepared by adding a commerciallyavailable matting agent (Sylysia 276 manufactured by Fuji SilysiaChemical, Ltd.) to a commercially available gloss emulsion paint(SILICONECERA UV FINISH COAT WB manufactured by Nippon Paint Co., Ltd.).The amount of the matting agent added was made to be 5% by mass to thegloss emulsion paint.

(Evaluation of Physical Properties of Paint Film)

For the paint compositions of the various Examples and ComparativeExamples, physical properties thereof when being formed into paint filmswere evaluated. The results are shown in Table 2-3. Here, measurementmethods of the various physical properties of the paint films were asfollows.

(Measurement of Gloss)

The gloss of the paint film made by application and drying each of theabove-mentioned paint compositions of the various Examples andComparative Examples were measured according to JIS K5600-4-7:1999.First, a paint composition was applied on a glass plate so that the filmthickness became about 40 μm, by using a 4-mil film applicator. Theresultant film was dried and thereafter, the 20° and 60° specularglosses were measured by using a gloss meter (haze-gloss metermanufactured by BYK-Gardner GmbH).

(Measurement of Hiding Power)

The hiding powers of the paint films made by application and drying ofthe above-mentioned paint compositions of the various Examples andComparative Examples were measured according to JIS K5600-4-7:1999.First, a paint composition was applied on a test paper for the hidingpower so that the film thickness became about 40 by using a 4-mil filmapplicator. The resultant was dried and thereafter, the Y_(b) value (Yvalue of a black ground) and the Y_(w) value (Y value of a white ground)were measured by using a spectroscopic colorimeter (SD5000 manufacturedby Nippon Denshoku Industries Co., Ltd.). Then, the hiding power(thereinafter, C.R.) was calculated from the values of the Y_(b) valueand the Y_(w) value according to the following expression.C.R. (%)=Y _(b) value/Y _(w) value×100(Measurement of Strength of Paint Film)

The strengths of the paint films made by application and drying of theabove-mentioned paint compositions of the various Examples andComparative Examples were measured according to JIS K5600-5-4:1999.First, a paint composition was applied on a glass plate so that the filmthickness became about 40 by using a 4-mil film applicator. Theresultant film was dried and thereafter subjected to a scratch hardnesstest using a wood drawing pencil (uni manufactured by Mitsubishi PencilCo., Ltd.).

TABLE 2-3 Gloss Hiding power Pencil 20° 60° Yb Yw C.R. (%) hardnessExample 2-1 1.2 2.4 87.4 89.6 97.5 4B Example 2-2 1.1 2.7 79.8 87.2 91.62B Example 2-3 1.1 2.6 83.2 88.3 94.2 4B Example 2-4 1.2 2.4 83.6 88.594.5 4B Example 2-5 1.1 2.7 83.4 88.5 94.3 B Example 2-7 1.1 2.4 83.788.4 94.7 4B Comparative 3.6 26 85.7 89.5 95.8 3B Example 2-1Comparative 1.1 2.3 80.9 86 94 lower than 6B Example 2-2 Comparative 2.517.9 85 89.4 95 F Example 2-3

The paint films of the paint compositions of the various Examples hadlower 20° and 60° specular glosses than the paint films of the paintcompositions of Comparative Example 2-1 and Comparative Example 2-3, andalso visually reduced gloss and developed a sufficient matte effect. Thelow-gloss property (matte effect) of these Examples was equal to that ofComparative Example 2-2, and reduced a gloss up to the degree of a glossreduction referred to as “matting (a 60° specular gloss of 5% or lower)”over the degree of a gloss reduction generally referred to as “70%gloss”, “50% gloss” or “30% gloss”. Further the paint films of the paintcompositions of the Examples had a C.R. value equal to or higher thanthat of the paint films of the paint compositions of the ComparativeExamples 2-1 to 2-3, and exhibited a practically sufficient hiding powernearly equal to that of the paint films of the paint compositions of theComparative Examples 2-1 to 2-3. In particular, the paint film ofExample 2-1 had a high C.R. value and could attain a higher hiding powerthan the paint films of the Comparative Examples.

It was further confirmed that the paint film of the paint composition ineach of the Examples had a sufficient pencil hardness and had apractically sufficient paint film strength.

As described above, the paint composition in each of the variousExamples had paint film physical properties (gloss, hiding power, andthe like) equal to or higher than the paint compositions of theComparative Examples. The composite pigments of the various Examples,only by being added to paint resins and the like and lightly mixed, canbe dispersed and formed into paints with labor saving, and can preparepaint films having the low-gloss property (matte effect) without beingadded separately with matting agents.

(Sensory Evaluation of Paint Film)

Paint films made by application and drying of the paint compositions ofExample 2-1, Comparative Example 2-2 and Comparative Example 2-3 weresubjected to sensory evaluations for the smoothness of the tactilefeeling and the ease of stain removal (stain removability).

(Evaluation of Tactile Feeling)

A paint composition was applied on a glass plate by using a 4-mil filmapplicator so that the film thickness became about 40 μm, and dried, andwas thereafter subjected to a finger touch test for the tactile feelingof a paint film. Specifically, 10 panel members touched the paint filmwith their fingers and rated superiority or inferiority of the tactilefeeling. The rating manner was such that a paint film exhibiting afirstly smooth tactile feeling was given 2 points; a paint filmexhibiting a secondly smooth tactile feeling, 1 point; and a paint filmexhibiting a most smoothless tactile feeling, 0 points. The averagevalue of points the 10 panel members gave was defined as an evaluationpoint of the tactile feeling. The results are shown in Table 2-4. Thepaint film of the paint composition of Example 2-1 resulted in beingbetter in the tactile feeling than those of Comparative Examples 2-2 and2-3.

TABLE 2-4 Tactile feeling Example 2-1 1.8 Comparative Example 2-2 0Comparative Example 2-3 1.2(Evaluation of Stain Removability)

A paint composition was applied so as to become 0.13 kg/m² on a slateboard (300 mm×200 mm×4 mm) on which a resin for sealer (Saibinol AD-7manufactured by Saiden Chemical Industry Co., Ltd.) had been applied anddried in advance, by using a brush. The obtained film was dried andthereafter, a color pencil and oleic acid were applied, and weresubjected to a 20 times-reciprocated wiping-out operation with a wastecloth impregnated with water having 5% of a neutral detergent.

In the paint film of the paint composition of Example 2-1, stain couldbe completely wiped out. By contrast, in the paint film of the paintcomposition (a commercially available flat emulsion paint) ofComparative Example 2-2, stain could hardly be removed, or the paintfilm resulted in peeling off. In the paint film of the paint composition(a combination of a commercially available gloss emulsion paint and acommercially available matting agent) of Comparative Example 2-3, stainresulted in being nearly removed.

Example of the Present Invention (the Third Invention of the PresentApplication) Example 3-1

In 819.6 g of pure water, 129 g of titanium dioxide (manufactured byIshihara Sangyo Kaisha, Ltd., average primary particle diameter: 0.24μm) was dispersed, to which 116.4 g of No. 3 sodium silicate aqueoussolution, and the resultant was then mixed to prepare a slurry oftitanium dioxide containing sodium silicate. The volume ratio (Va/Vb) ofthe volume Va of sodium silicate (in terms of SiO₂) and the volume Vb oftitanium dioxide in this slurry was 0.5, and the solid contentconcentration was 175 g/L. This solution was placed in a reaction vesselequipped with a stirrer and a thermometer, and the temperature wasraised to 75° C. with stirring. While maintaining the liquid temperatureat 75° C., 2.0% by mass sulfuric acid was added over 3 hours using amicro tube pump (MP-2001 manufactured by Tokyo Rikakikai Co, Ltd.) toadjust the pH of the solution to 7.0 to 7.5. Then, after aging for 1hour, an aggregate of titanium dioxide containing silica as a binder wasobtained in the solution. Then, the solution was filtrated using a No. 2filter paper, and the solid matter remaining on the filter paper waswashed with water, and again filtrated to obtain a wet filter cake ofthe above aggregate. The obtained wet filter cake was dried with heatingin a dryer set at 120° C. for 16 hours. The dry powder of the aggregatethus obtained was ground in a dry state using a grinder (Stud Mill 63Zmanufactured by Makino Mfg. Co., Ltd.), and then classified with aclassifier (TC-15M manufactured by Hosokawa Micron Corporation)(rotation speed: 3600 rpm, air flow rate: 1.5 m³/min) to obtain acomposite pigment in which titanium dioxide was fixed by silica. Anelectron microscope photograph of the composite pigment of Example 3-1is shown in FIG. 15.

Example 3-2

The addition amount of the silica source in Example 3-1 described abovewas increased. Specifically, by changing the used amount of pure waterto 923.4 g, and the addition amount of No. 3 sodium silicate aqueoussolution to 232.8 g, a slurry having a volume ratio (Va/Vb) of sodiumsilicate (in terms of SiO₂) to titanium dioxide of 1 and a solid contentconcentration of 175 g/L (the same as in Example 3-1) was prepared.Except for the above, a composite pigment in which titanium dioxide wasfixed by silica was prepared in the same procedures as in Example 3-1.FIG. 16 shows an electron microscope photograph of the composite pigmentof Example 3-2.

Example 3-3

The solid content concentration of the titanium dioxide slurrycontaining sodium silicate in Example 3-1 described above was increased.Specifically, by changing the used amount of pure water to 457.0 g, aslurry having a volume ratio (Va/Vb) of sodium silicate (in terms ofSiO₂) to titanium dioxide of 0.5 (the same as in Example 3-1) and asolid content concentration of 300 g/L was prepared. Except for theabove, a composite pigment in which titanium dioxide was fixed by silicawas prepared in the same procedures as in Example 3-1. FIG. 17 shows anelectron microscope photograph of the composite pigment of Example 3-3.

Example 3-4

The solid content concentration of the titanium dioxide slurrycontaining sodium silicate in Example 3-1 described above was lowered.Specifically, by changing the used amount of pure water to 1516.9 g, aslurry having a volume ratio (Va/Vb) of sodium silicate (in terms ofSiO₂) to titanium dioxide of 0.5 (the same as in Example 3-1) and asolid content concentration of 100 g/L was prepared. Except for theabove, a composite pigment in which titanium dioxide was fixed by silicawas prepared in the same procedures as in Example 3-1. FIG. 18 shows anelectron microscope photograph of the composite pigment of Example 3-4.

Example 3-5

By changing 129 g of titanium dioxide in Example 3-1 described above to129 g of nickel antimony titanium yellow (TY-50 manufactured by IshiharaSangyo Kaisha, Ltd., average primary particle diameter: 0.40 μm), aslurry having a volume ratio (Va/Vb) of sodium silicate (in terms ofSiO₂) to nickel antimony titanium yellow of 0.5 (the same as in Example3-1) and a solid content concentration of 175 g/L (the same as inExample 3-1) was prepared. Except for the above, a composite pigment inwhich nickel antimony titanium yellow was fixed by silica was preparedin the same procedures as in Example 3-1. FIG. 19 shows an electronmicroscope photograph of the composite pigment of Example 3-5.

Example 3-6

By changing 129 g of titanium dioxide in Example 3-1 described above to129 g of chrome antimony titanium buff (TY-300 manufactured by IshiharaSangyo Kaisha, Ltd., average primary particle diameter: 0.45 μm), aslurry having a volume ratio (Va/Vb) of sodium silicate (in terms ofSiO₂) to chrome antimony titanium buff of 0.5 (the same as in Example3-1) and a solid content concentration of 175 g/L (the same as inExample 3-1) was prepared. Except for the above, a composite pigment inwhich chrome antimony titanium buff was fixed by silica was prepared inthe same procedures as in Example 3-1. FIG. 20 shows an electronmicroscope photograph of the composite pigment of Example 3-6.

Example 3-7

By changing 129 g of titanium dioxide in Example 3-1 described above to161.1 g of red iron oxide (manufactured by Toda Kogyo Corp., averageprimary particle diameter: 0.25 μm), a slurry having a volume ratio(Va/Vb) of sodium silicate (in terms of SiO₂) to red iron oxide of 0.5(the same as in Example 3-1) and a solid content concentration of 210g/L was prepared. Except for the above, a composite pigment in which rediron oxide was fixed by silica was prepared in the same procedures as inExample 3-1. FIG. 21 shows an electron microscope photograph of thecomposite pigment of Example 3-7.

Example 3-8

By changing 129 g of titanium dioxide in Example 3-1 described above to72.2 g of ultramarine blue (manufactured by Daiichi Kasei Kogyo, averageprimary particle diameter: 0.2 μm), a slurry having a volume ratio(Va/Vb) of sodium silicate (in terms of SiO₂) to ultramarine blue of 0.5(the same as in Example 3-1) and a solid content concentration of 110g/L was prepared. Except for the above, a composite pigment in whichultramarine blue was fixed by silica was prepared in the same proceduresas in Example 3-1. FIG. 22 shows an electron microscope photograph ofthe composite pigment of Example 3-8.

Example 3-9

By changing 129 g of titanium dioxide in Example 3-1 described above to159.8 g of iron chromate composite oxide (manufactured by Shepherd ColorJapan, Inc., average primary particle diameter: 0.4 μm), a slurry havinga volume ratio (Va/Vb) of sodium silicate (in terms of SiO₂) to ironchromate composite oxide of 0.5 (the same as in Example 3-1) and a solidcontent concentration of 210 g/L was prepared. Except for the above, acomposite pigment in which the iron chromate composite oxide was fixedby silica was prepared in the same procedures as in Example 3-1. FIG. 23shows an electron microscope photograph of the composite pigment ofExample 3-9.

Comparative Example 3-1

A titanium dioxide pigment was prepared in accordance with theproduction method described in the Examples of JP 09-25429 A as follows.A slurry (slurry concentration: 350 g/L) of titanium dioxide(manufactured by Ishihara Sangyo Kaisha, Ltd., average primary particlediameter: 0.24 μm) was prepared, and was heated up to 70° C. withstirring, which pH was then adjusted to 4.0 with sulfuric acid dilutedto 35%. While maintaining the pH at 4.0 by adding the dilute sulfuricacid, 36.2 g (8% in terms of SiO₂ based on the mass of titanium dioxide)of No. 3 sodium silicate aqueous solution was added and aged for 30 min.Subsequently, 50 g (3% in terms of Al₂O₃ based on the mass of titaniumdioxide) of an aluminum sulfate aqueous solution was added while keepingthe temperature at 70° C., and then a sodium hydroxide aqueous solutionwas added to adjust the pH to 7.5, followed by aging for 1 hour.Subsequently, the slurry was filtrated with No. 2 filter paper and theresidue was washed and dried at 120° C. After drying, 1 g of methylhydrogen polysiloxane (KF-99 manufactured by Shin-Etsu Chemical Co.,Ltd.) was added thereto, mixed with a mixer and ground with a jet millto yield a titanium dioxide pigment. An electron microscope photographof the titanium dioxide pigment of Comparative Example 3-1 is shown inFIG. 24.

Comparative Example 3-2

As compared to Example 3-1 described above, the addition amount of thesilica source was reduced. Specifically, by changing the used amount ofpure water to 761.1 g and the used amount of No. 3 sodium silicateaqueous solution to 58.2 g, a slurry having a volume ratio (Va/Vb) ofsodium silicate to titanium dioxide of 0.25, and a solid contentconcentration of 175 g/L (the same as in Example 3-1) was prepared.Except for the above, a pigment of Comparative Example 3-2 was yieldedaccording to the same procedure as in Example 3-1. An electronmicroscope photograph of the pigment of Comparative Example 3-2 is shownin FIG. 25. As obvious from FIG. 25, in the sample of ComparativeExample 3-2, combining by silica did not progress so much as thecomposite pigments of the various Examples, and relatively smallparticles were dominant.

(Evaluation of Physical Properties of Powder)

Various powder physical properties of the composite pigments of thevarious Examples and the pigments of Comparative Examples 3-1 and 3-2were measured as follows. The results are shown in Table 3-1.Measurement methods of various powder physical properties are asfollows. “Sample” in the descriptions of the measurement method belowrefers to the respective composite pigments of the Examples and thepigments of Comparative Examples 3-1 and 3-2.

(Measurements of Particle Size Distribution and D90)

A particle size distribution was measured using a laserdiffraction/scattering-type particle size distribution measuringapparatus (LA-910 manufactured by HORIBA, Ltd.). More particularly, anaqueous solution in which 0.3% by mass of sodium hexametaphosphate wasdissolved was used as a dispersion medium, to which each sample wasmixed. The dispersion was circulated and stirred in the apparatus,irradiated with ultrasonic waves for 3 min to be dispersed thoroughly,and adjusted such that the transmittance of laser light became 73±3%.Then a volumetric particle size distribution was measured. In this case,the relative refractive index was set at 2.00-0.00i with respect toExamples 3-1 to 3-3, Example 3-6, and Comparative Examples 3-1 and 3-2,at 2.17-0.00i with respect to Example 3-4, and at 1.18-0.00i withrespect to Example 3-5, and the number of data fetching was set at 10times.

From the thus obtained particle size distribution data, the ratio ofparticles having a predetermined size with respect to the whole sample(the ratio of those having a particle diameter of 1 μm or more, theratio of those having a particle diameter of 2 μm or more, and the ratioof those having a particle diameter of 5 μm or more) were respectivelycalculated. Also, when the particle size distribution is expressed as acumulative distribution, the particle diameter at 90% of cumulativedistribution is defined as a diameter on cumulative 90% (D90).Incidentally, FIG. 26 shows a volume cumulative particle sizedistribution diagram of Example 3-1 as a representative of the variousExamples.

TABLE 3-1 Particle size distribution (%) >1 μm >2 μm >5 μm D90(μm)Example 3-1 88 35 2 2.9 Example 3-2 95 60 20 5.5 Example 3-3 80 36 5 3.7Example 3-4 65 10 0 1.9 Example 3-5 95 56 22 9.0 Example 3-6 93 88 4013.7 Example 3-7 93 70 39 10.6 Example 3-8 99 88 40 8.7 Example 3-9 9976 20 5.8 Comparative 26 1 0 1.2 Example 3-1 Comparative 17 1 0 1.1Example 3-2

As seen from Table 3-1, the abundance ratio of composite pigmentparticles having a particle diameter of 1 μm or more in the volumecumulative distribution measured by a laser diffraction/scattering-typeparticle size distribution measuring apparatus was 50% or more of thetotal with respect to any of the composite pigments of the variousExamples. With respect to any of the composite pigments of Examples 3-1to 3-3 and Examples 3-5 to 3-9, the abundance ratio of those having aparticle diameter of 2 μm or more in the volume particle sizedistribution was 30% or more of the total. Further, with respect to anyof Example 3-2 and Examples 3-5 to 3-9, the abundance ratio of compositepigment particles having a particle diameter of 5 μm or more in thevolume cumulative distribution was 20% or more of the total.

On the other hand, with respect to either of the pigments of ComparativeExamples 3-1 and 3-2, there were only about 20 to 30% of the pigmentparticles with respect to the total, which had a particle diameter of 1μm or more, and most of the particles had a particle diameter of lessthan 1 μm.

(Preparation of Paint Composition)

Paint compositions were prepared using the samples of Examples 3-1 to3-9 and Comparative Examples 3-1 and 3-2. Specifically, the rawmaterials listed in the following Table 3-2 were stirred for 5 min usinga dispersing machine (T. K. ROBOMIX manufactured by Tokushu Kika KogyoCo., Ltd, rotation speed: 3000 rpm), and then degassing was carried outwith a hybrid mixer (manufactured by KEYENCE CORPORATION, HM-500) toyield paint compositions.

TABLE 3-2 Example 3-1~3-6, 3-9, Comparative Example Example Example 3-23-7 3-8 Resin Acrylic emulsion resin, PRIMAL AC-2235, 32.2 parts 28.4parts 36.1 parts manufactured by Rohm and Haas Japan K.K. by mass bymass by mass Dispersant DISPERBYK-184 1.1 parts 1.3 parts 0.8 partsmanufactured by BYK Additives & Instruments by mass by mass by mass Tapwater 4.0 parts 3.1 parts 5.7 parts by mass by mass by mass EmulsifierTRITON CF-10 0.6 parts 0.5 parts 0.7 parts manufactured by Dow ChemicalCompany by mass by mass by mass Antifreezing Ethylene glycolmanufactured by Kanto Chemical 5.3 parts 4.7 parts 5.9 parts Agent Co.,Ltd. by mass by mass by mass pH adjuster 28% ammonia aqueous solution2.5 parts 2.2 parts 2.8 parts by mass by mass by mass Thickener 2%CELLOSIZE aqueous solution, 16.6 parts 14.6 parts 18.6 partsmanufactured by Dow Chemical Company by mass by mass by mass DefoamingADEKANATE B-748A 0.1 parts 0.1 parts 0.1 parts Agent manufactured byADEKA CORPORATION by mass by mass by mass Sample of 37.5 parts 45.0parts 29.6 parts Example or by mass by mass by mass Comparative Example

The paint composition thus obtained had a pigment volume concentration(PVC) of 40%, and a solid volume concentration (SVC) of 36.4%.

With respect to the pigment of Comparative Example 3-1, when the paintcomposition was prepared with the above blend, separation of the pigmentcomponents in the paint was severe, and therefore it was judged that thepaint is not worth undergoing the evaluations described later.Therefore, with respect to the pigment of Comparative Example 3-1, 70 gof a titanium dioxide pigment was blended into 88 g of an acryliclacquer varnish (solid content 26.5%) prepared by mixing 46.6 g of anacrylic resin (ACRYDIC A-141 manufactured by DIC Corporation) and 41.4 gof xylene in accordance with the blend described in JP 09-25429 A, andthe mixture (pigment/resin solid=3/1) was stirred with a paint shakerfor 10 min to prepare a paint. As a result of preparation of the paintcomposition, separation of the pigment components in the paintcomposition of Comparative Example 3-1 was not observed.

In the following description, the paint composition prepared using thesample of Example 3-1 by the above method is regarded as the paint ofExample 3-1. The same applies to other Examples and Comparative Example3-2.

In addition to the paint composition, the following were prepared aspaint compositions of the Comparative Examples.

Comparative Example 3-3

A commercially available matting paint composition (ECOFLAT 60manufactured by Nippon Paint Co., Ltd.) was prepared.

Comparative Example 3-4

A commercially available gloss emulsion paint (SILICONECERA UV FINISHCOAT WB manufactured by Nippon Paint Co., Ltd.) was prepared.

Comparative Example 3-5

A matting paint composition was prepared by adding a commerciallyavailable matting agent (Sylysia 276 manufactured by Fuji SilysiaChemical Ltd.) to the commercially available gloss emulsion paint(SILICONECERA UV FINISH COAT WB manufactured by Nippon Paint Co., Ltd.).The addition amount of the matting agent was 5% by mass with respect tothe gloss emulsion paint.

(Evaluation of Physical Properties of Paint Film)

Physical properties of various paint compositions of the Examples andComparative Example formed into paint films were evaluated. The resultsare shown in Table 3-3. The measurement methods for various physicalproperties of a paint film are as follows.

(Measurement of Gloss)

The gloss of a paint film obtained by applying and drying each of theabove-described various paint compositions of the Examples andComparative Examples was measured in accordance with JIS K 5600-4-7:1999. First, a paint composition was applied onto a glass plate using a4-mil film applicator up to the film thickness of about 40 μm. Afterdrying the film, the specular gloss was measured under each of geometricconditions of 20°, 60°, and 85° using a gloss meter (haze-gloss meter,manufactured by BYK-Gardner GmbH).

(Measurement of Hiding Power)

The hiding power of a paint film obtained by applying and drying each ofthe above-described various paint compositions of the Examples andComparative Examples was measured in accordance with JIS K 5600-4-1:1999. First, a paint composition was applied onto a test paper for thehiding power using a 4-mil film applicator up to the film thickness ofabout 40 μm. After drying the film, the Y_(b) value (Y value at blackpart) and Y_(w) value (Y value at white part) were respectively measuredusing a spectrophotometer (SD 5000 manufactured by Nippon DenshokuIndustries Co., Ltd.). From the values of Y_(b) value and Y_(w) value,the hiding power (thereafter, referred to as C.R.) was calculatedaccording to the following equation.C.R. (%)=Y _(b) value/Y _(w) value×100

TABLE 3-3 Hiding power Gloss C.R. 20° 60° 85° Yb Yw (%) Example 3-1 1.22.2 22.0 88.9 90.4 98.3 Example 3-2 1.3 2.3 8.6 86.0 89.3 96.3 Example3-3 1.2 2.3 11 86.9 89.7 96.9 Example 3-4 1.2 2.6 35.1 87.6 90.0 97.3Example 3-5 0.9 2.1 6.2 — — — Example 3-6 0.4 1.0 3.8 — — — Example 3-70.0 0.3 5.3 — — — Example 3-8 0.1 0.6 6.9 — — — Example 3-9 0.0 0.3 5.2— — — Comparative Example 3-1 1.9 23.1 76.5 86.1 88.4 97.4 ComparativeExample 3-2 1.5 6.9 69.7 87.4 90.1 96.9 Comparative Example 3-3 1.1 2.33.0 86.4 89.3 96.7 Comparative Example 3-4 39.7 73.7 96.4 85.6 88.7 96.6Comparative Example 3-5 2.5 17.9 41.7 85.0 89.4 95.1

As compared to the paint films of the paint compositions in ComparativeExamples 3-1, 3-2, 3-4, and 3-5, the paint film of the paint compositionin each of the Examples had a smaller specular gloss at 20° and 60°, andthe gloss was also apparently reduced, and a sufficient matte effect wasexhibited. The low-gloss property (matte effect) in each of the Exampleswas comparable to that in Comparative Example 3-3 having a high matteeffect, and the gloss was reduced even to the degree of a glossreduction referred to as “matting (specular gloss of 5% or less at 60°)”over the degree of a gloss reduction generally referred to as “70%gloss”, “50% gloss”, or “30% gloss”.

Further, with respect to the paint film of the paint composition in eachof the Examples, the specular gloss at 20° or 60° was sufficiently low,and the specular gloss at 85° was 40% or less to indicate that so-called85° gloss was also sufficiently reduced.

Further, with respect to the paint film of the paint composition in eachof Examples 3-1 to 3-3, and Examples 3-5 to 3-9, the specular gloss at85° was reduced to 30% or less, and with respect to the paint film ofthe paint composition in each of Example 3-2, and Examples 3-5 to 3-9,the specular gloss at 85° was reduced to 10% or less.

In addition, it was confirmed that the paint films of the Examples had ahiding power almost the same as those of the Comparative Examples, andhad a sufficient hiding power.

(Evaluation of Tactile Feeling of Paint Film)

Evaluation on the smoothness of the tactile feeling was performed oneach of the paint films obtained by applying and drying the paintcompositions in the Examples and Comparative Examples.

For quantifying the tactile feeling of a paint film as objective data, afriction coefficient was measured. Specifically, a paint composition wasapplied onto a glass plate using a 4-mil film applicator up to the filmthickness of about 40 μm. The applied composition was dried, and a MMD(mean friction coefficient variation) was then measured using a frictiontester (KES-SE manufactured by Kato Tech Co., Ltd.). The MMD (meanfriction coefficient variation) is used as an index indicating thefeeling of the roughness of a paint film. The measurement results areshown in Table 3-4 below. In Table 3-4, a tactile feeling at the time ofactually touching the paint film with a finger is shown in three grades(⊚: very smooth tactile feeling, ∘: smooth tactile feeling, X: highlyrough tactile feeling) along with the value of the aforementioned MMD.

TABLE 3-4 Tactile MMD Feeling Example 3-1 0.0085 ⊚ Example 3-2 0.0143 ◯Example 3-3 0.0054 ⊚ Example 3-4 0.0085 ⊚ Example 3-5 0.0157 ◯ Example3-6 0.0169 ◯ Example 3-7 0.0132 ◯ Example 3-8 0.0109 ◯ Example 3-90.0067 ⊚ Comparative Example 3-1 0.0119 ◯ Comparative Example 3-2 0.0152◯ Comparative Example 3-3 0.0253 X Comparative Example 3-4 0.0110 ◯Comparative Example 3-5 0.0117 ◯

A paint film of each of the paint compositions of the Examples had asmaller value of MMD (mean friction coefficient variation) compared tothe paint film of the paint composition of Comparative Example 3-3.Further, the value of MMD and the tactile feeling at the time ofactually touching the paint film are nearly correlated, and the tactilefeeling in each of the Examples was excellent (very smooth, or smooth)and was equal to or better than that of a general gloss paint giving apaint film with a smooth tactile feeling (Comparative Example 3-4).

As described above, a paint composition or paint film containing eachcomposite pigment of the present Examples are superior because they havelow-gloss property (matte effect), and are able to keep the good tactilefeeling of a paint film.

Example of the Present Invention (the Fourth Invention of the PresentApplication) Example 4-1

A mixture of a hydrate of titanium dioxide and zinc oxide as an additivefor calcination (0.8% by mass based on titanium dioxide) was calcined toobtain a titanium dioxide pigment. The average primary particle diameterof the titanium dioxide pigment was 0.24 In pure water, 129 g of thetitanium dioxide pigment and 82.8 g of precipitated (synthetic) calciumcarbonate (extender pigment Brilliant-1500 manufactured by ShiraishiCalcium Kaisha, Ltd., average primary particle diameter: 0.15 μm) weredispersed. To this solution, 116.4 g of No. 3 sodium silicate aqueoussolution was added and mixed to obtain a titanium dioxide pigment, and asodium silicate solution containing calcium carbonate (solid contentconcentration: 255 g/L) was prepared. This solution was placed in areaction vessel equipped with a stirrer and a thermometer, and thetemperature was raised to 75° C. with stirring. While maintaining theliquid temperature at 75° C., 2.0% by mass sulfuric acid was added over3 hours using a micro tube pump (MP-2001 manufactured by Tokyo RikakikaiCo, Ltd.) to adjust the pH of the solution to 7.0 to 7.5. Then, afteraging for 1 hour, a composite pigment of titanium dioxide/calciumcarbonate containing silica as a binder in the solution was obtained.Then, the solution was filtrated using a No. 2 filter paper, and thesolid matter remaining on the filter paper was washed with water, andagain filtrated to obtain a wet filter cake of the above compositepigment. The obtained wet filter cake was dried with heating in a dryerset at 120° C. for 16 hours. The dry powder of the composite pigmentthus obtained was ground in a dry state using a grinder (Stud Mill 63Zmanufactured by Makino Mfg. Co., Ltd.), and then classified with aclassifier (TC-15M manufactured by Hosokawa Micron Corporation)(rotation speed: 3600 rpm, air flow rate: 1.5 m³/min) to obtain acomposite pigment. An electron microscope photograph of the compositepigment of Example 4-1 is shown in FIG. 27. An enlarged view thereof isshown in FIG. 28.

Example 4-2

3.8 g of zinc sulfate heptahydrate was dissolved in 430 g of pure water.To the solution, 129 g of a titanium dioxide pigment (manufactured byIshihara Sangyo Kaisha, Ltd., average primary particle diameter: 0.24μm) was added to prepare a titanium dioxide dispersion containing zincsulfate heptahydrate (solid content concentration: 300 g/L). Thisdispersion was placed in a reaction vessel equipped with a stirrer and athermometer, and the temperature was raised to 75° C. with stirring.While maintaining the liquid temperature at 75° C., caustic soda (sodiumhydroxide) adjusted to 5.0% by mass was added over 1 hour by using amicro tube pump (MP-2001 manufactured by Tokyo Rikakikai Co, Ltd.) toadjust the pH of the solution to 8.0 to 8.5. Then after aging for 1hour, a titanium dioxide pigment, which surface was coated with zincoxide, was obtained in the solution. Further, 82.8 g of sedimentaryprecipitated (synthetic) calcium carbonate (extender pigmentBrilliant-1500 manufactured by Shiraishi Calcium Kaisha, Ltd., averageprimary particle diameter: 0.15 μm), 314.2 g of pure water, and 116.4 gof No. 3 sodium silicate aqueous solution were added and mixed toprepare a sodium silicate solution containing the titanium dioxidepigment and calcium carbonate (solid content concentration: 255 g/L).While maintaining the liquid temperature of this solution at 75° C.,2.0% by mass sulfuric acid was added over 3 hours using a micro tubepump (MP-2001 manufactured by Tokyo Rikakikai Co, Ltd.) to adjust the pHof the solution to 7.0 to 7.5. Then, after aging for 1 hour, a compositepigment of titanium dioxide/calcium carbonate containing silica as abinder was obtained in the solution. Then, the solution was filtratedusing a No. 2 filter paper, and the solid matter remaining on the filterpaper was washed with water, and again filtrated to obtain a wet filtercake of the above composite pigment. The obtained wet filter cake wasdried with heating in a dryer set at 120° C. for 16 hours. The drypowder of the composite pigment thus obtained was ground in a dry stateusing a grinder (Stud Mill 63Z manufactured by Makino Mfg. Co., Ltd.),and then classified with a classifier (TC-15M manufactured by HosokawaMicron Corporation) (rotation speed: 3600 rpm, air flow rate: 1.5m³/min) to obtain a composite pigment. An electron microscope photographof the composite pigment of Example 4-2 is shown in FIG. 29.

Example 4-3

Based on the production method of Example 4-1, a composite pigment notcontaining an extender pigment (calcium carbonate) was prepared. Thatis, 129 g of a titanium dioxide pigment obtained by a calcinationtreatment was dispersed in pure water, to which 116.4 g of No. 3 sodiumsilicate aqueous solution was added and followed by mixing to prepare asodium silicate solution containing the titanium dioxide pigment (solidcontent concentration: 175 g/L). A composite pigment of titanium dioxidewith silica as a binder was obtained in the same manner as in Example4-1 except for the above. FIG. 30 shows an electron microscopephotograph of the composite pigment of Example 4-3. A high magnificationview of FIG. 30 is shown in FIG. 33.

(Evaluation of Physical Properties of Powder)

Various powder physical properties of various composite pigments of theExamples were measured as follows. The results are shown in Tables 4-1and 4-2. Measurement methods of various powder physical properties areas follows. “Sample” in the descriptions of the measurement method belowrefers to the respective composite pigments of the various Examples.

(Measurement of Particle Size Distribution)

A particle size distribution was measured using a laserdiffraction/scattering-type particle size distribution measuringapparatus (LA-910 manufactured by HORIBA, Ltd.). More particularly, anaqueous solution in which 0.3% by mass of sodium hexametaphosphate wasdissolved was used as a dispersion medium, to which each sample wasmixed. The dispersion was circulated and stirred in an apparatus,irradiated with ultrasonic waves for 3 min to be dispersed thoroughly,and adjusted such that the transmittance of laser light became 73±3%.Then a volumetric particle size distribution was measured. The relativerefractive index was set at 2.00-0.00i, and the number of data fetchingwas set at 10 times. When the particle size distribution is expressed asa cumulative distribution, the particle diameter at 50% of thecumulative distribution is defined as a median diameter D50, and theparticle diameter at 90% of the cumulative distribution is defined as aD90. The values of D50 and D90 of each sample are shown in Table 4-1.

From the particle size distribution data, the ratios of particles havinga predetermined size with respect to the total sample (the ratio ofparticles having a particle diameter of 1 μm or more, the ratio ofparticles having a particle diameter of 2 μm or more, and the ratio ofparticles having a particle diameter of 5 μm or more) were calculatedrespectively. The results are shown in Table 4-1. FIG. 31 shows thevolume cumulative particle size distribution diagram of Example 4-1 as arepresentative of the various Examples.

TABLE 4-1 D50 (μm) D90 (μm) Example 4-1 5.3 8.5 Example 4-2 3.5 6.6Example 4-3 5.0 8.5

TABLE 4-2 Particle size distribution (%) >1 μm >2 μm >5 μm Example 4-199 97 55 Example 4-2 97 82 24 Example 4-3 100 97 47

As shown in Table 4-2, the abundance ratio of particles having aparticle diameter of 2 μm or more in the volume cumulative distributionmeasured by a laser diffraction/scattering-type particle sizedistribution measuring apparatus of each of the composite pigments ofthe Examples was 70% or more of the total. Further, the abundance ratioof particles having a particle diameter of 5 μm or more in the volumecumulative distribution of each of the composite pigments was 20% ormore (preferably 40% or more) of the total.

(Preparation of Paint Composition)

A paint composition was prepared using the sample in each of theExamples. The pigment volume concentration (PVC) of the paintcomposition was set to 40%, and the solid volume concentration (SVC) ofthe paint composition was set to 36.4%. Specifically, the raw materialsdescribed in the following Table 4-3 were stirred for 5 min using adispersing machine (T. K. ROBOMIX manufactured by Tokushu Kika KogyoCo., Ltd., rotation speed: 3000 rpm), and then degassed by a hybridmixer (HM-500 manufactured by KEYENCE CORPORATION) to obtain a paintcomposition.

In the following explanation, the paint compositions prepared by theabove method using the samples of Examples 4-1, 4-2, and 4-3 are treatedas the paint compositions of Examples 4-1, 4-2, and 4-3 respectively.

TABLE 4-3 Example Example 4-1, 4-2 4-3 Resin Acrylic emulsion resin,PRIMAL AC-2235, 33.4 parts 32.2 parts manufactured by Rohm and HaasJapan K. K. by mass by mass Dispersant DISPERBYK-184 1.0 parts 1.1 partsmanufactured by BYK Additives & Instruments by mass by mass (Aminevalue: 15 mg KOH/g) Pure water 4.2 parts 4.0 parts by mass by massEmulsifier TRITON CF-10 0.6 parts 0.6 parts manufactured by Dow ChemicalCompany by mass by mass Antifreezing Ethylene glycol manufactured byKanto Chemical Co., Inc. 5.5 parts 5.3 parts Agent by mass by mass pHadjuster 28% ammonia aqueous solution 2.6 parts 2.5 parts by mass bymass Thickener 2% CELLOSIZE aqueous solution, 17.3 parts 16.6 partsmanufactured by Dow Chemical Company by mass by mass Defoaming ADEKANATEB-748A 0.1 parts 0.1 parts Agent manufactured by ADEKA CORPORATION bymass by mass Sample 35.3 parts 37.5 parts by mass by mass(Measurement of Viscosity of Paint)

For the paint composition in each of the Examples, a viscosity wasmeasured using a Brookfield B-type rotary viscometer (TVB-10 Viscometermanufactured by Toki Sangyo Co., Ltd.). The measurement results areshown in Table 4-4. The measurement was performed under the followingconditions. The paint composition was put in a 50 mL graduated cylinder,and the viscosity was measured at each of the rotation speeds (6 rpm and60 rpm).

Rotor: TM4

Measurement temperature: 25° C.

TABLE 4-4 Viscosity (Pa · s) 6 rpm 60 rpm Example 4-1 12.2 2.8 Example4-2 14.3 2.6 Example 4-3 23.0 4.1

It was confirmed that the paint compositions of the Examples had lowviscosity and good handling.

In addition to the above-mentioned paint compositions, the followingwere prepared as paint compositions of the Comparative Examples.

Comparative Example 4-1

A commercially available matting paint composition (ECOFLAT 60manufactured by Nippon Paint Co., Ltd.) was prepared.

Comparative Example 4-2

A commercially available gloss emulsion paint (SILICONECERA UV FINISHCOAT WB manufactured by Nippon Paint Co., Ltd.) was prepared.

Comparative Example 4-3

A matting paint composition was prepared by adding a commerciallyavailable matting agent (Sylysia 276 manufactured by Fuji SilysiaChemical Ltd.) to a commercially available gloss emulsion paint(SILICONECERA UV FINISH COAT WB manufactured by Nippon Paint Co., Ltd.).The addition amount of the matting agent was 5% by mass with respect tothe gloss emulsion paint.

(Evaluation of Physical Properties of Paint Film)

Physical properties of various paint compositions of the Examples andComparative Examples formed into paint films were evaluated. The resultsare shown in Table 4-5. The measurement methods for various physicalproperties of a paint film are as follows.

(Measurement of Gloss)

The gloss of a paint film obtained by applying and drying each of theabove-described various paint compositions of the Examples andComparative Examples was measured in accordance with JIS K 5600-4-7:1999. First, a paint composition was applied onto a glass plate using a4-mil film applicator up to the film thickness of about 40 μm. Afterdrying the film, the specular gloss was measured under each of geometricconditions of 20°, 60°, and 85° using a gloss meter (haze-gloss metermanufactured by BYK-Gardner GmbH).

(Measurement of Hiding Power)

The hiding power of a paint film obtained by applying and drying each ofthe above-described various paint compositions of the Examples andComparative Examples was measured in accordance with JIS K 5600-4-1:1999. First, a paint composition was applied onto a test paper for thehiding power using a 4-mil film applicator up to the film thickness ofabout 40 μm. After drying the film, the Y_(b) value (Y value at blackpart) and Y_(w) value (Y value at white part) were respectively measuredusing a spectrophotometer (SD 5000 manufactured by Nippon DenshokuIndustries Co., Ltd.). From the values of Y_(b) value and Y_(w) value,the hiding power (thereinafter, referred to as C.R.) was calculatedaccording to the following equation.C.R. (%)=Y _(b) value/Y _(w) value×100

TABLE 4-5 Hiding power Gloss C.R. 20° 60° 85° Yb Yw (%) Example 4-1 1.22.4 4.7 82.9 87.8 94.4 Example 4-2 1.2 2.3 9.1 85.8 89.0 96.4 Example4-3 1.2 2.2 6.6 84.9 88.5 95.9 Comparative Example 4-1 1.1 2.3 3.0 86.489.3 96.7 Comparative Example 4-2 39.7 73.7 96.4 85.6 88.7 96.6Comparative Example 4-3 2.5 17.9 41.7 85.0 89.4 95.1

As compared to the paint films of the paint compositions in ComparativeExamples 4-2 and 4-3, the paint film of the paint composition in each ofthe Examples had a smaller specular gloss at 20° and 60°, and the glosswas also apparently reduced, and a sufficient matte effect wasexhibited. The low-gloss property (matte effect) in each of the Examplesresulted in reducing the gloss even to the degree of a gloss reductionreferred to as “matting (specular gloss of 5% or less at 60°)” over thedegree of a gloss reduction generally referred to as “70% gloss”, “50%gloss”, or “30% gloss”. Further, with respect to the paint film of thepaint composition in each of the Examples, the specular gloss at 20° or60° was sufficiently low, and the specular gloss at 85° was 10% or lessto indicate that so-called 85° gloss was also remarkably reduced.

In addition, it was confirmed that the paint films of the Examples had ahiding power almost the same as those of the Comparative Examples, andhad a sufficient hiding power.

As described above, with respect to the paint composition of eachExample, not only the specular glosses at 20° and 60°, but also thespecular gloss at 85° was highly reduced. The degree of a glossreduction was the same level as Comparative Example 4-1 having a highmatte effect (commercially available flat emulsion paint).

In this regard, it is prerequisite for expression of the high matteeffect that the pigment component of the paint of Comparative Example4-1 is strongly dispersed. On the other hand, in the case of thecomposite pigments of the Examples, the paint can be prepared merely byadding the same to a paint resin and mixing it lightly, and therefore ithas an advantage of labor saving in dispersion and formation of a paint.

(Evaluation of Tactile Feeling of Paint Film)

Evaluation of the smoothness of the tactile feeling was performed on apaint film obtained by applying and drying each of the paintcompositions in the Examples and Comparative Examples.

For quantifying the tactile feeling of the paint film as objective data,a friction coefficient was measured. Specifically, a paint compositionwas applied onto a glass plate using a 4-mil film applicator up to thefilm thickness of about 40 μm. The applied composition was dried, and aMMD (mean friction coefficient variation) was then measured using afriction tester (KES-SE, manufactured by Kato Tech Co., Ltd.). The MMD(mean friction coefficient variation) is used as an index indicating thefeeling of the roughness of a paint film. The measurement results areshown in Table 4-6 below. In Table 4-6, a tactile feeling at the time ofactually touching the paint film with a finger is shown in three grades(⊚: very smooth tactile feeling, ∘: smooth tactile feeling, X: highlyrough tactile feeling) along with the value of the aforementioned MMD.

TABLE 4-6 Tactile MMD feeling Example 4-1 0.0127 ◯ Example 4-2 0.0126 ◯Example 4-3 0.0169 ◯ Comparative Example 4-1 0.0253 X ComparativeExample 4-2 0.0110 ◯ Comparative Example 4-3 0.0117 ◯

A paint film of any of the paint compositions of the Examples had asmaller value of MMD (mean friction coefficient variation) compared tothe paint film of the paint composition of Comparative Example 4-1.Further, the value of MMD and the tactile feeling at the time ofactually touching the paint film are nearly correlated, and the tactilefeeling in any of the Examples was excellent (smooth).

As described above, a paint composition or paint film containing eachcomposite pigment of the present Examples are superior, because thesmooth tactile feeling of a paint film can be realized while reducingremarkably the gloss including 85° gloss, and good handling can beexhibited.

Examples of the Present Invention (the Fifth Invention of the PresentApplication)

The present Examples are those re-collected by appropriately using theabove-mentioned Examples and Comparative Examples of the first inventionof the present application to the fourth invention of the presentapplication. Specifically, the present Examples are as follows.

(Evaluation of Various Powder Physical Properties (Particle SizeDistribution, Specific Surface Area, Oil Absorption))

Examples 5-1 to 5-4 correspond to the composite pigments of Examples 1-1to 1-4 in the above-mentioned [Examples of the present invention (thefirst invention of the present application)], respectively. Therefore,the various powder physical properties (particle size distribution,specific surface area, oil absorption) of these Examples were determinedaccording to (Evaluation of physical properties of powder), (Measurementof particle size distribution), (Measurement of specific surface area)and (Measurement of oil absorption), and specifically, were as shown inTable 1-1. Then, Comparative Examples 1-1 to 1-5 in Table 1-1 are dealtwith as Comparative Examples 5-1 to 5-5. The re-collected results areshown in Table 5-1.

TABLE 5-1 Particle size Specific distribution surface Oil D10 D50 D90area absorption (μm) (μm) (μm) (m²/g) (ml/100 g) Example 5-1 1.7 5.612.9 63.9 53 Example 5-2 2.4 8.4 19.1 64.2 86 Example 5-3 1.5 4.5 10.855.1 47 Example 5-4 0.8 1.3 2.3 9.2 — (not measured) Comparative Example5-1 1.3 3.0 9.4 1.7 10 Comparative Example 5-2 2.0 4.7 12.9 0.7 10Comparative Example 5-3 2.2 9.4 23.3 0.8 10 Comparative Example 5-4 4.37.4 12.2 191.6 180 Comparative Example 5-5 3.0 7.4 13.5 3.5 36

Further, Examples 5-5 to 5-11 in Table 5-2 correspond to the compositepigments of Examples 2-1 to 2-7 in the above-mentioned [Examples of thepresent invention (the second invention of the present application)],respectively. Therefore, the various powder physical properties(particle size distribution (respective particle diameters (mediandiameter) at cumulative 50% and cumulative 90%), specific surface area,oil absorption and composition) of these Examples were determinedaccording to (Evaluation of physical properties of powder),(Measurements of median diameter and diameter on cumulative 90%),(Measurement of specific surface area), (Measurement of oil absorption)and (Measurements of compositions of composite pigments and the like) inthe above-mentioned [Examples of the present invention (the secondinvention of the present application)], and specifically, were as shownin Table 2-1. In the present Examples, Comparative Example 2-1 in Table2-1 is dealt with as Comparative Example 5-9.

Then, Examples 5-12 and 5-13 correspond to the composite pigments ofExamples 4-1 and 4-2 in the above-mentioned [Examples of the presentinvention (the fourth invention of the present application)],respectively. Therefore, the various powder physical properties(particle size distribution (respective particle diameters (mediandiameter) at cumulative 50% and cumulative 90%) of these Examples weredetermined according to (Evaluation of physical properties of powder)and (Measurement of particle size distribution) in the above-mentioned[Examples of the present invention (the fourth invention of the presentapplication)], and specifically, were as shown in Table 4-1. Here, thespecific surface area, the oil absorption and the composition were alsodetermined according to (Measurement of specific surface area),(Measurement of oil absorption) and (Measurements of compositions ofcomposite pigments and the like) in the above-mentioned [Examples of thepresent invention (the second invention of the present application)].These results are shown collectively in Table 5-2.

TABLE 5-2 Specific surface Oil D50 D90 area absorption Composition (massratio) (μm) (μm) (m²/g) (ml/100 g) TiO₂ CaCO₃ BaSO₄ SiO₂ Example 5-5 1.41.8 21.5 44 64 25 — 11 Example 5-6 1.0 1.7 19.6 45 47 43 — 10 Example5-7 1.4 2.3 22.4 47 67 19 — 14 Example 5-8 1.4 2.5 27.2 52 55 27 — 18Example 5-9 1.8 3.3 28.8 50 61 24 — 15 Example 5-10 1.4 1.4 19.3 42 5929 — 12 Example 5-11 1.6 2.8 24.5 39 51 — 37 12 Example 5-12 5.3 8.515.2 52 66 22 11 Example 5-13 3.5 6.6 18.9 56 66 20 14 Comparative 0.60.9 14.2 21 61 39 — — Example 5-9

Then, Table 5-3 collectively shows, as Examples 5-5 to 5-9 and Examples5-11 to 5-13, results of respective ratios (a ratio of particles of 1 μmor larger in particle diameter, a ratio of particles of 2 μm or largerin particle diameter, and a ratio of particles of 5 μm or larger inparticle diameter) accounted for by particles having predetermined sizesin a sample as a whole, which were calculated from data of the particlesize distribution determined according to (Measurement of particle sizedistribution) in the above-mentioned [Examples of the present invention(the second invention of the present application)] and [Examples of thepresent invention (the fourth invention of the present application)].Here, the results of Examples 5-12 and 5-13 are shown as Examples 4-1and 4-2 in Table 4-2, respectively. A volume cumulative particle sizedistribution diagram of Example 5-12 is FIG. 31 showing the volumecumulative particle size distribution diagram of Example 4-1corresponding to this Example.

TABLE 5-3 Particle size distribution (%) >1 μm >2 μm >5 μm Example 5-572 16 0 Example 5-6 51 6 0 Example 5-7 80 19 0 Example 5-8 77 21 0Example 5-9 89 40 3 Example 5-11 84 30 1 Example 5-12 99 97 55 Example5-13 97 82 24

From Table 5-3, in the composite pigments (produced by using aninorganic color pigment containing zinc) of Examples 5-12 and 5-13, theabundance ratio of composite pigment particles of 2 μm or larger inparticle diameter was 70% or higher in the whole, in a volume cumulativedistribution measured by the laser diffraction/scattering-type particlesize distribution measuring apparatus. Then in the volume cumulativedistribution, the abundance ratio of the composite pigment particles of5 μm or larger was 20% or higher (preferably 40% or higher) in thewhole.

Preparations of the composite pigments of Examples 5-1 to 5-4 and thepaint compositions using a matting agent of Comparative Examples 5-1 to5-5 in Table 5-4 were as described in (Preparation of paintcompositions) in the above-mentioned [Examples of the present invention(the first invention of the present application)], and hence, thedescriptions in Table 5-4 are the same as in Table 1-2.

TABLE 5-4 Examples 5-1 to 5-4, Comparative Comparative Examples ExamplesComparative Comparative 5-6 to 5-8 5-1 to 5-3 Example 5-4 Example 5-5Resin Acrylic emulsion resin, 43.5 parts 40.7 parts 46.4 parts 49.3parts PRIMAL AC-2235 by mass by mass by mass by mass manufactured byRohm and Haas Japan K. K. Dispersant DISPERBYK-184 0.5 parts 0.7 parts0.4 parts 0.2 parts manufactured by by mass by mass by mass by mass BYKAdditives & Instruments (amine value: 15 mg KOH/g) Pure water 7.8 parts7.5 parts 8.1 parts 8.4 parts by mass by mass by mass by mass EmulsifierTRITON CF-10 0.8 parts 0.8 parts 0.9 parts 0.9 parts manufactured by bymass by mass by mass by mass Dow Chemical Company Antifreezing Ethyleneglycol, 7.1 parts 6.7 parts 7.6 parts 8.1 parts agent manufactured by bymass by mass by mass by mass Kanto Chemical Co., Inc. pH adjuster 28%ammonia aqueous 0.2 parts 0.2 parts 0.2 parts 0.3 parts solution by massby mass by mass by mass Thickener 2% CELLOSIZE aqueous 22.4 parts 21.0parts 23.9 parts 25.4 parts solution manufactured by by mass by mass bymass by mass Dow Chemical Company Defoaming ADEKANATE B-748A 0.1 parts0.1 parts 0.2 parts 0.2 parts agent manufactured by by mass by mass bymass by mass ADEKA CORPORATION Sample 17.6 parts 22.3 parts 12.3 parts7.2 parts by mass by mass by mass by mass

Preparations of the samples of Examples 5-5 to 5-9 and Examples 5-11 to5-13 and the paint composition using a mixed powder of ComparativeExample 5-9 in Table 5-5 were as described in (Preparation of paintcompositions) in the above-mentioned [Examples of the present invention(the second invention of the present application)] and [Examples of thepresent invention (the fourth invention of the present application)],and hence, the descriptions in Table 5-5 are as described in Tables 2-2and 4-3. The preparations were performed, as described therein, bysetting the pigment volume concentration (PVC) of the paint compositionsat 40% and the solid volume concentration (SVC) thereof at 36.4%.

TABLE 5-5 Resin Acrylic emulsion resin, PRIMAL 33.4 parts AC-2235,manufactured by Rohm and by mass Haas Japan K. K. DispersantDISPERBYK-184 (amine value: 15 mg 1.0 parts KOH/g), manufactured by BYKby mass Additives & Instruments Pure water 4.2 parts by mass EmulsifierTRITON CF-10, manufactured by Dow 0.6 parts Chemical Company by massAntifreezing Ethylene glycol, manufactured by Kanto 5.5 parts AgentChemical Co., Inc. by mass pH adjuster 28% ammonia aqueous solution 2.6parts by mass Thickener 2% CELLOSIZE aqueous solution 17.3 partsmanufactured by Dow Chemical Company by mass Defoaming ADEKANATE B-748Amanufactured by 0.1 parts Agent ADEKA CORPORATION by mass Sample of 35.3parts Example or by mass Comparative Example

The viscosities of the composite pigments of Examples 5-1 to 5-4 andvarious paint compositions using a matting agent of Comparative Examples5-1 to 5-8 in Table 5-6 were measured as described in (Measurement ofthe paint viscosity) in the above-mentioned [Examples of the presentinvention (the first invention of the present application)], andspecifically, were as shown in Table 1-3.

TABLE 5-6 Viscosity (Pa · s) 6 rpm 60 rpm Example 5-1 8.9 1.7 Example5-2 17.2 3.2 Example 5-3 10.6 2.1 Example 5-4 9.4 1.9 ComparativeExample 5-1 5.3 1.1 Comparative Example 5-2 4.9 1.1 Comparative Example5-3 4.4 0.9 Comparative Example 5-4 30.7 5.7 Comparative Example 5-5 5.01.0 Comparative Example 5-6 12.5 2.5 Comparative Example 5-7 12.2 2.4Comparative Example 5-8 12.6 2.6

The paint compositions of the various Examples were lower in theviscosity than the paint composition of Comparative Example 5-4 usingsilica as a matting agent, and exhibited good handling. The viscosities(handling) of the Examples resulted in being equal to or lower thanthose of the paint compositions (Comparative Examples 5-6 to 5-8) usinga mixture of silica and barium sulfate as a matting agent; and someExamples attained low viscosities (high handling) nearly equal to theviscosities of the paint compositions (Comparative Examples 5-1 to 5-3and 5-5) using an extender pigment (barium sulfate), resin beads or thelike as a matting agent.

For Examples 5-5 to 5-9 and Examples 5-11 to 5-13, the viscosities ofthe various paint compositions were measured as described in(Measurement of viscosity of paint) in the above-mentioned [Examples ofthe present invention (the fourth invention of the presentapplication)], and their results are shown in Table 5-7.

It was confirmed that any of the paint compositions of the Examples inTable 5-7 was good in handling.

TABLE 5-7 Viscosity (Pa · s) 6 rpm 60 rpm Example 5-5 10.5 1.9 Example5-6 12.6 2.7 Example 5-7 12.4 2.7 Example 5-8 15.1 3.2 Example 5-11 15.33.2 Example 5-12 12.2 2.8 Example 5-13 14.3 2.6(Evaluation of Physical Properties of Paint Film)

For the paint compositions of the various Examples and ComparativeExamples, the results of the evaluation of the physical properties ofthe paint films are collectively shown in Tables 5-8 and 5-9. Themeasurement methods of the various physical properties of the paintfilms were as described in (Evaluation of physical properties of paintfilm), (Evaluation of gloss) and (Measurement of hiding power) in theabove-mentioned [Examples of the present invention (the first inventionof the present application)]. Therefore, Examples 5-1 to 5-4 andComparative Examples 5-1 to 5-8 in Table 5-8 are shown as Examples 1-1to 1-4 and Comparative Examples 1-1 to 1-8 in Table 1-4, respectively.Then, in the Examples and Comparative Examples in Table 5-9, the resultsof the measurement of the paint film strength are shown together. Themeasurement of the paint film strength was performed as described in(Measurement of strength of paint film) in the above-mentioned [Examplesof the present invention (the second invention of the presentapplication)]. Therefore, the measurement results of the paint filmstrengths of Examples 5-5 to 5-11 and Comparative Example 5-9 in Table5-9 are shown in Examples 2-1 to 2-7 and Comparative Example 2-1 inTable 2-3 together with the glosses (20°, 60°) and the hiding powers(Yb, Yw and C.R.).

Here, Comparative Example 5-10 in Table 5-9 shows the results used acommercially available matting paint composition (ECOFLAT 60manufactured by Nippon Paint Co., Ltd.); Comparative Example 5-11therein shows the results used a commercially available gloss emulsionpaint (SILICONECERA UV FINISH COAT WB manufactured by Nippon Paint Co.,Ltd.); Comparative Example 5-12 therein shows the results used a mattingpaint composition prepared by adding a commercially available mattingagent (Sylysia 276 manufactured by Fuji Silysia Chemical Ltd., theaddition amount was 5% by mass to a gloss emulsion paint) to thecommercially available gloss emulsion paint (SILICONECERA UV FINISH COATWB manufactured by Nippon Paint Co., Ltd.); the measurement results ofthe paint film strengths of Comparative Examples 5-10 and 5-11 arerespectively shown as Comparative Examples 2-1 and 2-3 in Table 2-3 inthe above-mentioned [Examples of the present invention (the secondinvention of the present application)]; and the glosses (20°, 60° and85°) and the hiding powers (Y_(b), Y_(w) and C.R.) of ComparativeExamples 5-10 to 5-12 are respectively shown as Comparative Examples 4-1to 4-3 in Table 4-5 in the above-mentioned [Examples of the presentinvention (the fourth invention of the present application)].

TABLE 5-8 Gloss Hiding power 20° 60° 85° Yb Yw C.R. (%) Example 5-1 0.55.0 4.8 6.8 81.3 8.3 Example 5-2 0.4 3.0 2.7 10.6 80.9 13.0 Example 5-30.5 3.3 5.1 9.5 81.1 11.7 Example 5-4 0.5 4.1 40.7 7.0 81.6 8.6Comparative Example 5-1 1.5 16.7 30.8 4.6 80.1 5.7 Comparative Example5-2 0.8 9.4 10.6 5.0 80.9 6.1 Comparative Example 5-3 1.2 13.0 11.0 4.880.9 5.9 Comparative Example 5-4 0.4 3.3 6.1 9.4 81.2 11.6 ComparativeExample 5-5 1.5 13.8 6.6 4.3 81.4 5.3 Comparative Example 5-6 0.4 5.55.9 5.5 80.8 6.8 Comparative Example 5-7 0.4 5.8 6.3 5.2 81.3 6.4Comparative Example 5-8 0.5 6.9 5.9 5.2 81.4 6.4

As shown in Table 5-8, the paint films of the transparent matting paintcompositions of Examples 5-1 to 5-4 had lower 20° and 60° specularglosses than the paint films of the transparent matting paintcompositions of Comparative Examples 5-1 to 5-3 (matting agent of bariumsulfate), Comparative Example 5-5 (matting agent of resin beads) andComparative Examples 5-6 to 5-8 (matting agent of a mixture of bariumsulfate and silica), and visually reduced gloss and developed asufficient matte effect. The low-gloss property (matte effect) of theseExamples was equal to that of Comparative Example 5-4 having a strongmatte effect, and a gloss thereof was reduced to the degree of a glossreduction referred to as “matting (a 60° specular gloss of 5% or lower)”over the degree of a gloss reduction generally referred to as “70%gloss”, “50% gloss” or “30% gloss”.

Then, the hiding powers of the paint films of the transparent mattingpaint compositions of the Examples 5-1 to 5-3 reduced the 85° speculargloss to 10% or lower, sufficiently reducing so-called 85° gloss.

Further, the hiding powers of the paint films of the transparent mattingpaint compositions of the Examples were nearly equal to those of theComparative Examples, and maintained low hiding powers. Such transparentmatting paint compositions do not hinder color of the base layer evenwhen applied onto a color base layer, and is therefore appropriate as atopcoat matting paint composition which is applied onto the color baselayer.

These facts were as already described in (Measurement of hiding power)in the above-mentioned [Examples of the present invention (the firstinvention of the present application)].

TABLE 5-9 Hiding power Gloss C.R. Pencil 20° 60° 85° Yb Yw (%) hardnessExample 5-5 1.2 2.4 24.2 87.4 89.6 97.5 4B Example 5-6 1.1 2.7 36.6 79.887.2 91.6 2B Example 5-7 1.1 2.6 29.7 83.2 88.3 94.2 4B Example 5-8 1.22.4 30.2 83.6 88.5 94.5 4B Example 5-9 1.1 2.7 28.3 83.4 88.5 94.3 BExample 5-11 1.1 2.4 26.8 83.7 88.4 94.7 4B Example 5-12 1.2 2.4 4.782.9 87.8 94.4 — Example 5-13 1.2 2.3 9.1 85.8 89.0 96.4 — Comparative3.6 26 46.4 85.7 89.5 95.8 3B Example 5-9 Comparative 1.1 2.3 3.0 80.986 94 Lower Example 5-10 than 6B Comparative 39.7 73.7 96.4 85.6 88.796.6 — Example 5-11 Comparative 2.5 17.9 41.7 85.0 89.4 95.1 F Example5-12

The paint films of the paint compositions of Examples 5-5 to 5-13 hadlower 20° and 60° specular glosses than the paint films of the paintcompositions of Comparative Examples 5-9, Comparative Example 5-11 andComparative Example 5-12, and visually reduced gloss and developed asufficient matte effect. The low-gloss property (matte effect) of theseExamples was equal to that of Comparative Example 5-10 (a commerciallyavailable flat emulsion paint), and gloss thereof was reduced even tothe degree of a gloss reduction referred to as “matting (a 60° speculargloss of 5% or lower)” over the degree of a gloss reduction generallyreferred to as “70% gloss”, “50% gloss” or “30% gloss”. Then, the paintfilms of the paint compositions of Examples 5-12 and 5-13 hadsufficiently low 20° and 60° specular glosses, and moreover also had a85° specular gloss of 10% or lower, highly reducing so-called 85° gloss.

Further, the paint films of the paint compositions of Examples 5-5 to5-13 had a practically sufficient hiding power nearly equal to that ofthe paint compositions of Comparative Examples 5-9 to 5-12. Inparticular, the paint film of Example 5-1 had a high C.R. value andcould attain a higher hiding power than that of the ComparativeExamples.

Further, it was confirmed that the paint film of the paint compositionin each of the Examples had a sufficient pencil hardness and had apractically sufficient paint film strength.

These facts were as already described in (Measurement of strength ofpaint film) in the above-mentioned [Examples of the present invention(the second invention of the present application)] and (Measurement ofhiding power) in the above-mentioned [Examples of the present invention(the fourth invention of the present application)].

As described above, the paint compositions of Examples 5-5 to 5-13 hadpaint film physical properties (gloss, hiding power and the like) equalto or higher than those of the Comparative Examples, and highly reducedalso the 20° and 60° specular glosses to degrees nearly equal toComparative Example 5-10.

Here, the paint of Comparative Example 5-10 needed strong dispersion ofpigment components in order to develop a high matte effect. By contrast,using each composite pigment of the Examples was superior in that: laborsaving in dispersion and formation of paints could be achieved merely byadding the same to a paint resin and mixing it lightly; and the paintfilms having the low-gloss property (matte effect) could be preparedwithout separate addition of a matting agent.

(Evaluation of Uneven Loss of Gloss of Paint Film)

Evaluation of the uneven loss of gloss of the paint films made byapplication and drying of the transparent matting paint compositions ofExamples 5-1 to 5-4 and Comparative Examples 5-1 to 5-8 was as describedin (Evaluation of uneven loss of gloss of paint film) in theabove-mentioned [Examples of the present invention (the first inventionof the present application)]. Specifically, Examples 5-1 to 5-4 andComparative Examples 5-1 to 5-8 in Table 5-10 are shown as Examples 1-1to 1-4 and Comparative Examples 1-1 to 1-8 in Table 1-5, respectively.

TABLE 5-10 Uneven loss of gloss 20° 60° 85° Example 5-1 0.0 0.3 0.1Example 5-2 0.1 0.5 0.1 Example 5-3 0.1 0.3 0.3 Example 5-4 0.1 0.6 1.7Comparative Example 5-1 0.1 1.4 1.4 Comparative Example 5-2 0.0 0.4 1.1Comparative Example 5-3 0.2 0.5 2.0 Comparative Example 5-4 0.1 0.4 0.5Comparative Example 5-5 0.0 0.3 0.2 Comparative Example 5-6 0.1 0.7 0.2Comparative Example 5-7 0.1 1.3 0.1 Comparative Example 5-8 0.1 0.6 0.1

The values of the specular glosses (20°, 60°, 85°) in Table 5-10 and thevisual (uneven loss of gloss) impression of the real paint filmsexhibited a rough correlation, and it was likely that the larger thenumerical values of the standard deviations, the greater the uneven lossof gloss of the paint films. Specifically, the paint films ofComparative Examples 5-1 to 5-3 containing barium sulfate as a singlesubstance had a remarkable uneven loss of gloss of their paint films. Bycontrast, it was confirmed that similarly to the other ComparativeExamples, the paint films of Examples 5-1 to 5-4 exhibited no unevenloss of gloss, and the gloss was uniformly reduced at any place of thepaint films. These facts were as already described in (Evaluation ofuneven loss of gloss of paint film) in the above-mentioned [Examples ofthe present invention (the first invention of the present application)].

(Evaluation of Tactile Feeling of Paint Film)

Evaluation of the tactile feeling of the paint films made by applicationand drying of the transparent matting paint compositions of Examples 5-1to 5-4 and Comparative Examples 5-1 to 5-8 was as described in(Evaluation of tactile feeling of paint film) in the above-mentioned[Examples of the present invention (the first invention of the presentapplication)]. Specifically, the tactile feeling evaluation results ofthe paint films of Examples 5-1 to 5-4 and Comparative Examples 5-1 to5-8 in Table 5-11 are shown in Examples 1-1 to 1-4 and ComparativeExamples 1-1 to 1-8 in Table 1-6, respectively. Therefore, evaluation ofMMD (variation in the mean friction coefficient) in the Table andevaluation of the tactile feeling when a paint film was actually touchedwith a finger (∘: smooth tactile feeling, Δ: rough tactile feeling, X:highly rough tactile feeling) were as described in (Evaluation oftactile feeling of paint film) in the above-mentioned [Examples of thepresent invention (the first invention of the present application)].

TABLE 5-11 Tactile MMD Feeling Example 5-1 0.0105 ◯ Example 5-2 0.0100 ◯Example 5-3 0.0070 ◯ Example 5-4 0.0066 ◯ Comparative Example 5-1 0.0285X Comparative Example 5-2 0.0207 Δ Comparative Example 5-3 0.0664 XComparative Example 5-4 0.0190 ◯ Comparative Example 5-5 0.0075 ◯Comparative Example 5-6 0.0291 Δ Comparative Example 5-7 0.0202 ΔComparative Example 5-8 0.0262 Δ

Any of the paint films of the paint compositions of Examples 5-1 to 5-4had better tactile feeling (smoother) than the paint films (ComparativeExamples 5-1 to 5-3 and Comparative Examples 5-6 to 5-8), any of whichcontained an extender pigment (barium sulfate). The degree of thesmoothness was a degree nearly equal to or higher than that of paintfilms usually having smooth tactile feeling, like the paint films(Comparative Examples 5-4 and 5-5), which contained silica or resinbeads as a matting agent.

As described above, the paint compositions and paint films in which thecomposite pigments of the present Examples were blended were superior inthat these maintained good handling and had a low-gloss property (matteeffect), and could attain good paint film tactile feeling.

These facts were as described in (Evaluation of tactile feeling of paintfilm) in the above-mentioned [Examples of the present invention (thefirst invention of the present application)].

The measurement results of the evaluation of the tactile feeling of thepaint films of Examples 5-5 and 5-11 to 5-13 and Comparative Examples5-10 to 5-12 in Table 5-12 were results measured as described in(Evaluation of tactile feeling of paint film) in the above-mentioned[Examples of the present invention (the fourth invention of the presentapplication)] and were also results measured as described in (Evaluationof tactile feeling of paint film) in the above-mentioned [Examples ofthe present invention (the first invention of the present application)].Therefore, the results of the tactile feeling evaluation of the Examples5-12 and 5-13 and Comparative Examples 5-10 to 5-12 in Table 5-12 areshown as Examples 4-1 and 4-2 and Comparative Examples 4-1 to 4-3 inTable 4-6.

Any of the paint films of the paint compositions of Examples 5-5 and5-11 to 5-13 had a lower value of MMD (variation in mean frictioncoefficient) than the paint film of the paint composition of ComparativeExample 5-11. Then, the value of MMD and the tactile feeling of thepaint films when being touched with a finger exhibited a roughcorrelation, and the tactile feeling of the Examples was good (smooth).These facts were as described in (Evaluation of tactile feeling of paintfilm) in the above-mentioned [Examples of the present invention (thefourth invention of the present application)].

TABLE 5-12 Tactile MMD Feeling Example 5-5 0.0112 ◯ Example 5-11 0.0079◯ Example 5-12 0.0127 ◯ Example 5-13 0.0126 ◯ Comparative Example 5-100.0110 ◯ Comparative Example 5-11 0.0253 X Comparative Example 5-120.0117 ◯(Evaluation of Stain Removability)

As described in comparison of Example 2-1 with Comparative Examples 2-2and 2-3 in (Evaluation of stain removability) in the above-mentioned[Examples of the present invention (the second invention of the presentapplication)], although in the paint film of the paint composition ofExample 5-5, stain could be completely wiped out, in the paint film ofthe paint composition (a commercially available flat emulsion paint) ofComparative Example 5-11, stain could hardly be removed, or the paintfilm resulted in peeling off; and it was found that in the paint film ofthe paint composition (a combination of a commercially available glossemulsion paint and a commercially available matting agent) ofComparative Example 5-12, stain could be nearly removed.

As described above, the paint compositions and the paint films in whichthe composite pigments of the Examples were blended were superior inthat these highly reduced gloss including 85° gloss and simultaneouslycould attain a smooth paint film tactile feeling and moreover exhibiteda good handling.

INDUSTRIAL APPLICABILITY

The composite pigment of the present invention, since being able tohighly attain all of good handling, a low-gloss property (matte effect)and good paint film tactile feeling, can appropriately be used for paintfilms having the low-gloss property (matte effect), matting paint filmsand the like for buildings and vehicles and the like.

The composite pigment of the present invention can reduce a gloss ofpaint films by modifying inorganic color pigments, and can be used invarious applications as a pigment having the low-gloss property (matteeffect), a matting pigment and the like. Further the composite pigmentof the present invention, since also when being blended in paint films,both the property of having a low gloss and a luster and the goodtactile feeling of the paint films can simultaneously be satisfied, canbe used for paint films having the low-gloss property (matte effect),matting paint films and the like.

The composite pigment of the present invention, since being able toachieve labor saving in dispersion and formation of paints can beachieved and being capable of developing a high matte effect, isappropriate as a pigment to be used for paint compositions requiring thelow-gloss property (matte effect).

The invention claimed is:
 1. A composite pigment comprising: extenderpigment particles comprising barium sulfate; and an inorganic compoundcomprising silica, the composite pigment in which a plurality of theextender pigment particles are aggregated in a granular shape with theinorganic compound interposed between the particles, wherein a contentratio of the extender pigment particles and the inorganic compound inthe composite pigment is 0.3 to 3 parts by volume of the inorganiccompound to 1 part by volume of the extender pigment particles, andwherein the composite pigment having a diameter on cumulative 50% (D50)in a volume cumulative distribution measured by a laserdiffraction/scattering-type particle size distribution measuringapparatus is 1 μm or more and 15 μm or less.
 2. A matting pigmentcomprising the composite pigment set forth in claim
 1. 3. A method forproducing a composite pigment comprising: adjusting a pH of a slurrycontaining an inorganic compound source and extender pigment particlesso that an inorganic compound derived from the inorganic compound sourceis precipitated to fix the extender pigment particles, the compositepigment in which a plurality of the extender pigment particles areaggregated in a granular shape with the inorganic compound interposedbetween the particles, wherein the extender pigment particles comprisebarium sulfate and the inorganic compound comprises silica, wherein acontent ratio of the extender pigment particles and the inorganiccompound in the composite pigment is 0.3 to 3 parts by volume of theinorganic compound to 1 part by volume of the extender pigmentparticles, and wherein the composite pigment having a diameter oncumulative 50% (D50) in a volume cumulative distribution measured by alaser diffraction/scattering-type particle size distribution measuringapparatus is 1 μm or more and 15 μm or less.
 4. A paint compositioncomprising the composite pigment set forth in claim 1 and a resin. 5.The paint composition according to claim 4, further comprising adispersant having an amine value.
 6. A paint film comprising the paintcomposition set forth in claim
 4. 7. A paint composition comprising thematting pigment set forth in claim 2, and a resin.
 8. A matting pigmentconsisting essentially of: a composite pigment in which a plurality ofextender pigment particles are aggregated in a granular shape with aninorganic compound interposed between the particles, wherein theextender pigment particles comprise barium sulfate and the inorganiccompound comprises silica, wherein a content ratio of the extenderpigment particles and the inorganic compound in the composite pigment is0.3 to 3 parts by volume of the inorganic compound to 1 part by volumeof the extender pigment particles, and wherein the matting pigmenthaving a diameter on cumulative 50% (D50) in a volume cumulativedistribution measured by a laser diffraction/scattering-type particlesize distribution measuring apparatus is 1 μm or more and 15 μm or less.9. The composite pigment according to claim 1, wherein the inorganiccompound has an aggregating property used to form the granular shapewith the inorganic compound interposed between the extender pigmentparticles.
 10. The method according to claim 3, wherein the inorganiccompound has an aggregating property used to form the granular shapewith the inorganic compound interposed between the extender pigmentparticles.
 11. The matting pigment according to claim 8, wherein theinorganic compound has an aggregating property used to form the granularshape with the inorganic compound interposed between the extenderpigment particles.